From 7d1982b4e335c1b184406b7566f6041bfe313c35 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 15 Jun 2018 02:30:47 +0200 Subject: bpf: fix panic in prog load calls cleanup While testing I found that when hitting error path in bpf_prog_load() where we jump to free_used_maps and prog contained BPF to BPF calls that were JITed earlier, then we never clean up the bpf_prog_kallsyms_add() done under jit_subprogs(). Add proper API to make BPF kallsyms deletion more clear and fix that. Fixes: 1c2a088a6626 ("bpf: x64: add JIT support for multi-function programs") Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov --- include/linux/filter.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/filter.h') diff --git a/include/linux/filter.h b/include/linux/filter.h index 45fc0f5000d8..297c56fa9cee 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -961,6 +961,9 @@ static inline void bpf_prog_kallsyms_del(struct bpf_prog *fp) } #endif /* CONFIG_BPF_JIT */ +void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp); +void bpf_prog_kallsyms_del_all(struct bpf_prog *fp); + #define BPF_ANC BIT(15) static inline bool bpf_needs_clear_a(const struct sock_filter *first) -- cgit v1.3-8-gc7d7 From 9facc336876f7ecf9edba4c67b90426fde4ec898 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 15 Jun 2018 02:30:48 +0200 Subject: bpf: reject any prog that failed read-only lock We currently lock any JITed image as read-only via bpf_jit_binary_lock_ro() as well as the BPF image as read-only through bpf_prog_lock_ro(). In the case any of these would fail we throw a WARN_ON_ONCE() in order to yell loudly to the log. Perhaps, to some extend, this may be comparable to an allocation where __GFP_NOWARN is explicitly not set. Added via 65869a47f348 ("bpf: improve read-only handling"), this behavior is slightly different compared to any of the other in-kernel set_memory_ro() users who do not check the return code of set_memory_ro() and friends /at all/ (e.g. in the case of module_enable_ro() / module_disable_ro()). Given in BPF this is mandatory hardening step, we want to know whether there are any issues that would leave both BPF data writable. So it happens that syzkaller enabled fault injection and it triggered memory allocation failure deep inside x86's change_page_attr_set_clr() which was triggered from set_memory_ro(). Now, there are two options: i) leaving everything as is, and ii) reworking the image locking code in order to have a final checkpoint out of the central bpf_prog_select_runtime() which probes whether any of the calls during prog setup weren't successful, and then bailing out with an error. Option ii) is a better approach since this additional paranoia avoids altogether leaving any potential W+X pages from BPF side in the system. Therefore, lets be strict about it, and reject programs in such unlikely occasion. While testing I noticed also that one bpf_prog_lock_ro() call was missing on the outer dummy prog in case of calls, e.g. in the destructor we call bpf_prog_free_deferred() on the main prog where we try to bpf_prog_unlock_free() the program, and since we go via bpf_prog_select_runtime() do that as well. Reported-by: syzbot+3b889862e65a98317058@syzkaller.appspotmail.com Reported-by: syzbot+9e762b52dd17e616a7a5@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov --- include/linux/filter.h | 60 ++++++++++++++++++++++++++++++++------------------ kernel/bpf/core.c | 55 +++++++++++++++++++++++++++++++++++++++------ kernel/bpf/syscall.c | 4 +--- 3 files changed, 87 insertions(+), 32 deletions(-) (limited to 'include/linux/filter.h') diff --git a/include/linux/filter.h b/include/linux/filter.h index 297c56fa9cee..108f9812e196 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -469,7 +469,8 @@ struct sock_fprog_kern { }; struct bpf_binary_header { - unsigned int pages; + u16 pages; + u16 locked:1; u8 image[]; }; @@ -671,15 +672,18 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) -#ifdef CONFIG_ARCH_HAS_SET_MEMORY static inline void bpf_prog_lock_ro(struct bpf_prog *fp) { +#ifdef CONFIG_ARCH_HAS_SET_MEMORY fp->locked = 1; - WARN_ON_ONCE(set_memory_ro((unsigned long)fp, fp->pages)); + if (set_memory_ro((unsigned long)fp, fp->pages)) + fp->locked = 0; +#endif } static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) { +#ifdef CONFIG_ARCH_HAS_SET_MEMORY if (fp->locked) { WARN_ON_ONCE(set_memory_rw((unsigned long)fp, fp->pages)); /* In case set_memory_rw() fails, we want to be the first @@ -687,34 +691,30 @@ static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) */ fp->locked = 0; } +#endif } static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) { - WARN_ON_ONCE(set_memory_ro((unsigned long)hdr, hdr->pages)); -} - -static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr) -{ - WARN_ON_ONCE(set_memory_rw((unsigned long)hdr, hdr->pages)); -} -#else -static inline void bpf_prog_lock_ro(struct bpf_prog *fp) -{ -} - -static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) -{ -} - -static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) -{ +#ifdef CONFIG_ARCH_HAS_SET_MEMORY + hdr->locked = 1; + if (set_memory_ro((unsigned long)hdr, hdr->pages)) + hdr->locked = 0; +#endif } static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr) { +#ifdef CONFIG_ARCH_HAS_SET_MEMORY + if (hdr->locked) { + WARN_ON_ONCE(set_memory_rw((unsigned long)hdr, hdr->pages)); + /* In case set_memory_rw() fails, we want to be the first + * to crash here instead of some random place later on. + */ + hdr->locked = 0; + } +#endif } -#endif /* CONFIG_ARCH_HAS_SET_MEMORY */ static inline struct bpf_binary_header * bpf_jit_binary_hdr(const struct bpf_prog *fp) @@ -725,6 +725,22 @@ bpf_jit_binary_hdr(const struct bpf_prog *fp) return (void *)addr; } +#ifdef CONFIG_ARCH_HAS_SET_MEMORY +static inline int bpf_prog_check_pages_ro_single(const struct bpf_prog *fp) +{ + if (!fp->locked) + return -ENOLCK; + if (fp->jited) { + const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); + + if (!hdr->locked) + return -ENOLCK; + } + + return 0; +} +#endif + int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap); static inline int sk_filter(struct sock *sk, struct sk_buff *skb) { diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 1061968adcc1..a9e6c04d0f4a 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -598,6 +598,8 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, bpf_fill_ill_insns(hdr, size); hdr->pages = size / PAGE_SIZE; + hdr->locked = 0; + hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), PAGE_SIZE - sizeof(*hdr)); start = (get_random_int() % hole) & ~(alignment - 1); @@ -1448,6 +1450,33 @@ static int bpf_check_tail_call(const struct bpf_prog *fp) return 0; } +static int bpf_prog_check_pages_ro_locked(const struct bpf_prog *fp) +{ +#ifdef CONFIG_ARCH_HAS_SET_MEMORY + int i, err; + + for (i = 0; i < fp->aux->func_cnt; i++) { + err = bpf_prog_check_pages_ro_single(fp->aux->func[i]); + if (err) + return err; + } + + return bpf_prog_check_pages_ro_single(fp); +#endif + return 0; +} + +static void bpf_prog_select_func(struct bpf_prog *fp) +{ +#ifndef CONFIG_BPF_JIT_ALWAYS_ON + u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); + + fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; +#else + fp->bpf_func = __bpf_prog_ret0_warn; +#endif +} + /** * bpf_prog_select_runtime - select exec runtime for BPF program * @fp: bpf_prog populated with internal BPF program @@ -1458,13 +1487,13 @@ static int bpf_check_tail_call(const struct bpf_prog *fp) */ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) { -#ifndef CONFIG_BPF_JIT_ALWAYS_ON - u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); + /* In case of BPF to BPF calls, verifier did all the prep + * work with regards to JITing, etc. + */ + if (fp->bpf_func) + goto finalize; - fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; -#else - fp->bpf_func = __bpf_prog_ret0_warn; -#endif + bpf_prog_select_func(fp); /* eBPF JITs can rewrite the program in case constant * blinding is active. However, in case of error during @@ -1485,6 +1514,8 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) if (*err) return fp; } + +finalize: bpf_prog_lock_ro(fp); /* The tail call compatibility check can only be done at @@ -1493,7 +1524,17 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) * all eBPF JITs might immediately support all features. */ *err = bpf_check_tail_call(fp); - + if (*err) + return fp; + + /* Checkpoint: at this point onwards any cBPF -> eBPF or + * native eBPF program is read-only. If we failed to change + * the page attributes (e.g. allocation failure from + * splitting large pages), then reject the whole program + * in order to guarantee not ending up with any W+X pages + * from BPF side in kernel. + */ + *err = bpf_prog_check_pages_ro_locked(fp); return fp; } EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 0f62692fe635..35dc466641f2 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1353,9 +1353,7 @@ static int bpf_prog_load(union bpf_attr *attr) if (err < 0) goto free_used_maps; - /* eBPF program is ready to be JITed */ - if (!prog->bpf_func) - prog = bpf_prog_select_runtime(prog, &err); + prog = bpf_prog_select_runtime(prog, &err); if (err < 0) goto free_used_maps; -- cgit v1.3-8-gc7d7 From 6d5fc1957989266006db6ef3dfb9159b42cf0189 Mon Sep 17 00:00:00 2001 From: Toshiaki Makita Date: Thu, 14 Jun 2018 11:07:42 +0900 Subject: xdp: Fix handling of devmap in generic XDP Commit 67f29e07e131 ("bpf: devmap introduce dev_map_enqueue") changed the return value type of __devmap_lookup_elem() from struct net_device * to struct bpf_dtab_netdev * but forgot to modify generic XDP code accordingly. Thus generic XDP incorrectly used struct bpf_dtab_netdev where struct net_device is expected, then skb->dev was set to invalid value. v2: - Fix compiler warning without CONFIG_BPF_SYSCALL. Fixes: 67f29e07e131 ("bpf: devmap introduce dev_map_enqueue") Signed-off-by: Toshiaki Makita Acked-by: Yonghong Song Acked-by: Jesper Dangaard Brouer Signed-off-by: Daniel Borkmann --- include/linux/bpf.h | 12 ++++++++++++ include/linux/filter.h | 16 ++++++++++++++++ kernel/bpf/devmap.c | 14 ++++++++++++++ net/core/filter.c | 21 ++++----------------- 4 files changed, 46 insertions(+), 17 deletions(-) (limited to 'include/linux/filter.h') diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 995c3b1e59bf..7df32a3200f7 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -488,12 +488,15 @@ void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth); /* Map specifics */ struct xdp_buff; +struct sk_buff; struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key); void __dev_map_insert_ctx(struct bpf_map *map, u32 index); void __dev_map_flush(struct bpf_map *map); int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, struct net_device *dev_rx); +int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb, + struct bpf_prog *xdp_prog); struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key); void __cpu_map_insert_ctx(struct bpf_map *map, u32 index); @@ -586,6 +589,15 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, return 0; } +struct sk_buff; + +static inline int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, + struct sk_buff *skb, + struct bpf_prog *xdp_prog) +{ + return 0; +} + static inline struct bpf_cpu_map_entry *__cpu_map_lookup_elem(struct bpf_map *map, u32 key) { diff --git a/include/linux/filter.h b/include/linux/filter.h index 108f9812e196..b615df57b7d5 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -19,6 +19,7 @@ #include #include #include +#include #include @@ -802,6 +803,21 @@ static inline bool bpf_dump_raw_ok(void) struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, const struct bpf_insn *patch, u32 len); +static inline int __xdp_generic_ok_fwd_dev(struct sk_buff *skb, + struct net_device *fwd) +{ + unsigned int len; + + if (unlikely(!(fwd->flags & IFF_UP))) + return -ENETDOWN; + + len = fwd->mtu + fwd->hard_header_len + VLAN_HLEN; + if (skb->len > len) + return -EMSGSIZE; + + return 0; +} + /* The pair of xdp_do_redirect and xdp_do_flush_map MUST be called in the * same cpu context. Further for best results no more than a single map * for the do_redirect/do_flush pair should be used. This limitation is diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index a7cc7b3494a9..642c97f6d1b8 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -345,6 +345,20 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, return bq_enqueue(dst, xdpf, dev_rx); } +int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb, + struct bpf_prog *xdp_prog) +{ + int err; + + err = __xdp_generic_ok_fwd_dev(skb, dst->dev); + if (unlikely(err)) + return err; + skb->dev = dst->dev; + generic_xdp_tx(skb, xdp_prog); + + return 0; +} + static void *dev_map_lookup_elem(struct bpf_map *map, void *key) { struct bpf_dtab_netdev *obj = __dev_map_lookup_elem(map, *(u32 *)key); diff --git a/net/core/filter.c b/net/core/filter.c index 3d9ba7e5965a..e7f12e9f598c 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3214,20 +3214,6 @@ err: } EXPORT_SYMBOL_GPL(xdp_do_redirect); -static int __xdp_generic_ok_fwd_dev(struct sk_buff *skb, struct net_device *fwd) -{ - unsigned int len; - - if (unlikely(!(fwd->flags & IFF_UP))) - return -ENETDOWN; - - len = fwd->mtu + fwd->hard_header_len + VLAN_HLEN; - if (skb->len > len) - return -EMSGSIZE; - - return 0; -} - static int xdp_do_generic_redirect_map(struct net_device *dev, struct sk_buff *skb, struct xdp_buff *xdp, @@ -3256,10 +3242,11 @@ static int xdp_do_generic_redirect_map(struct net_device *dev, } if (map->map_type == BPF_MAP_TYPE_DEVMAP) { - if (unlikely((err = __xdp_generic_ok_fwd_dev(skb, fwd)))) + struct bpf_dtab_netdev *dst = fwd; + + err = dev_map_generic_redirect(dst, skb, xdp_prog); + if (unlikely(err)) goto err; - skb->dev = fwd; - generic_xdp_tx(skb, xdp_prog); } else if (map->map_type == BPF_MAP_TYPE_XSKMAP) { struct xdp_sock *xs = fwd; -- cgit v1.3-8-gc7d7 From 9262478220eac908ae6e168c3df2c453c87e2da3 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 20 Jun 2018 17:24:09 -0700 Subject: bpf: enforce correct alignment for instructions After commit 9facc336876f ("bpf: reject any prog that failed read-only lock") offsetof(struct bpf_binary_header, image) became 3 instead of 4, breaking powerpc BPF badly, since instructions need to be word aligned. Fixes: 9facc336876f ("bpf: reject any prog that failed read-only lock") Signed-off-by: Eric Dumazet Cc: Daniel Borkmann Cc: Martin KaFai Lau Cc: Alexei Starovoitov Signed-off-by: David S. Miller --- include/linux/filter.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include/linux/filter.h') diff --git a/include/linux/filter.h b/include/linux/filter.h index b615df57b7d5..20f2659dd829 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -472,7 +472,9 @@ struct sock_fprog_kern { struct bpf_binary_header { u16 pages; u16 locked:1; - u8 image[]; + + /* Some arches need word alignment for their instructions */ + u8 image[] __aligned(4); }; struct bpf_prog { -- cgit v1.3-8-gc7d7 From 85782e037f8aba8922dadb24a1523ca0b82ab8bc Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 28 Jun 2018 23:34:59 +0200 Subject: bpf: undo prog rejection on read-only lock failure Partially undo commit 9facc336876f ("bpf: reject any prog that failed read-only lock") since it caused a regression, that is, syzkaller was able to manage to cause a panic via fault injection deep in set_memory_ro() path by letting an allocation fail: In x86's __change_page_attr_set_clr() it was able to change the attributes of the primary mapping but not in the alias mapping via cpa_process_alias(), so the second, inner call to the __change_page_attr() via __change_page_attr_set_clr() had to split a larger page and failed in the alloc_pages() with the artifically triggered allocation error which is then propagated down to the call site. Thus, for set_memory_ro() this means that it returned with an error, but from debugging a probe_kernel_write() revealed EFAULT on that memory since the primary mapping succeeded to get changed. Therefore the subsequent hdr->locked = 0 reset triggered the panic as it was performed on read-only memory, so call-site assumptions were infact wrong to assume that it would either succeed /or/ not succeed at all since there's no such rollback in set_memory_*() calls from partial change of mappings, in other words, we're left in a state that is "half done". A later undo via set_memory_rw() is succeeding though due to matching permissions on that part (aka due to the try_preserve_large_page() succeeding). While reproducing locally with explicitly triggering this error, the initial splitting only happens on rare occasions and in real world it would additionally need oom conditions, but that said, it could partially fail. Therefore, it is definitely wrong to bail out on set_memory_ro() error and reject the program with the set_memory_*() semantics we have today. Shouldn't have gone the extra mile since no other user in tree today infact checks for any set_memory_*() errors, e.g. neither module_enable_ro() / module_disable_ro() for module RO/NX handling which is mostly default these days nor kprobes core with alloc_insn_page() / free_insn_page() as examples that could be invoked long after bootup and original 314beb9bcabf ("x86: bpf_jit_comp: secure bpf jit against spraying attacks") did neither when it got first introduced to BPF so "improving" with bailing out was clearly not right when set_memory_*() cannot handle it today. Kees suggested that if set_memory_*() can fail, we should annotate it with __must_check, and all callers need to deal with it gracefully given those set_memory_*() markings aren't "advisory", but they're expected to actually do what they say. This might be an option worth to move forward in future but would at the same time require that set_memory_*() calls from supporting archs are guaranteed to be "atomic" in that they provide rollback if part of the range fails, once that happened, the transition from RW -> RO could be made more robust that way, while subsequent RO -> RW transition /must/ continue guaranteeing to always succeed the undo part. Reported-by: syzbot+a4eb8c7766952a1ca872@syzkaller.appspotmail.com Reported-by: syzbot+d866d1925855328eac3b@syzkaller.appspotmail.com Fixes: 9facc336876f ("bpf: reject any prog that failed read-only lock") Cc: Laura Abbott Cc: Kees Cook Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: Alexei Starovoitov --- include/linux/filter.h | 56 ++++++++------------------------------------------ kernel/bpf/core.c | 30 +-------------------------- 2 files changed, 9 insertions(+), 77 deletions(-) (limited to 'include/linux/filter.h') diff --git a/include/linux/filter.h b/include/linux/filter.h index 20f2659dd829..300baad62c88 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -470,9 +470,7 @@ struct sock_fprog_kern { }; struct bpf_binary_header { - u16 pages; - u16 locked:1; - + u32 pages; /* Some arches need word alignment for their instructions */ u8 image[] __aligned(4); }; @@ -481,7 +479,7 @@ struct bpf_prog { u16 pages; /* Number of allocated pages */ u16 jited:1, /* Is our filter JIT'ed? */ jit_requested:1,/* archs need to JIT the prog */ - locked:1, /* Program image locked? */ + undo_set_mem:1, /* Passed set_memory_ro() checkpoint */ gpl_compatible:1, /* Is filter GPL compatible? */ cb_access:1, /* Is control block accessed? */ dst_needed:1, /* Do we need dst entry? */ @@ -677,46 +675,24 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default) static inline void bpf_prog_lock_ro(struct bpf_prog *fp) { -#ifdef CONFIG_ARCH_HAS_SET_MEMORY - fp->locked = 1; - if (set_memory_ro((unsigned long)fp, fp->pages)) - fp->locked = 0; -#endif + fp->undo_set_mem = 1; + set_memory_ro((unsigned long)fp, fp->pages); } static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) { -#ifdef CONFIG_ARCH_HAS_SET_MEMORY - if (fp->locked) { - WARN_ON_ONCE(set_memory_rw((unsigned long)fp, fp->pages)); - /* In case set_memory_rw() fails, we want to be the first - * to crash here instead of some random place later on. - */ - fp->locked = 0; - } -#endif + if (fp->undo_set_mem) + set_memory_rw((unsigned long)fp, fp->pages); } static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr) { -#ifdef CONFIG_ARCH_HAS_SET_MEMORY - hdr->locked = 1; - if (set_memory_ro((unsigned long)hdr, hdr->pages)) - hdr->locked = 0; -#endif + set_memory_ro((unsigned long)hdr, hdr->pages); } static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr) { -#ifdef CONFIG_ARCH_HAS_SET_MEMORY - if (hdr->locked) { - WARN_ON_ONCE(set_memory_rw((unsigned long)hdr, hdr->pages)); - /* In case set_memory_rw() fails, we want to be the first - * to crash here instead of some random place later on. - */ - hdr->locked = 0; - } -#endif + set_memory_rw((unsigned long)hdr, hdr->pages); } static inline struct bpf_binary_header * @@ -728,22 +704,6 @@ bpf_jit_binary_hdr(const struct bpf_prog *fp) return (void *)addr; } -#ifdef CONFIG_ARCH_HAS_SET_MEMORY -static inline int bpf_prog_check_pages_ro_single(const struct bpf_prog *fp) -{ - if (!fp->locked) - return -ENOLCK; - if (fp->jited) { - const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); - - if (!hdr->locked) - return -ENOLCK; - } - - return 0; -} -#endif - int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap); static inline int sk_filter(struct sock *sk, struct sk_buff *skb) { diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index a9e6c04d0f4a..1e5625d46414 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -598,8 +598,6 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, bpf_fill_ill_insns(hdr, size); hdr->pages = size / PAGE_SIZE; - hdr->locked = 0; - hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), PAGE_SIZE - sizeof(*hdr)); start = (get_random_int() % hole) & ~(alignment - 1); @@ -1450,22 +1448,6 @@ static int bpf_check_tail_call(const struct bpf_prog *fp) return 0; } -static int bpf_prog_check_pages_ro_locked(const struct bpf_prog *fp) -{ -#ifdef CONFIG_ARCH_HAS_SET_MEMORY - int i, err; - - for (i = 0; i < fp->aux->func_cnt; i++) { - err = bpf_prog_check_pages_ro_single(fp->aux->func[i]); - if (err) - return err; - } - - return bpf_prog_check_pages_ro_single(fp); -#endif - return 0; -} - static void bpf_prog_select_func(struct bpf_prog *fp) { #ifndef CONFIG_BPF_JIT_ALWAYS_ON @@ -1524,17 +1506,7 @@ finalize: * all eBPF JITs might immediately support all features. */ *err = bpf_check_tail_call(fp); - if (*err) - return fp; - - /* Checkpoint: at this point onwards any cBPF -> eBPF or - * native eBPF program is read-only. If we failed to change - * the page attributes (e.g. allocation failure from - * splitting large pages), then reject the whole program - * in order to guarantee not ending up with any W+X pages - * from BPF side in kernel. - */ - *err = bpf_prog_check_pages_ro_locked(fp); + return fp; } EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); -- cgit v1.3-8-gc7d7