From 791caeb084c57e3a4d648cf1ee799d1f70c0ef4e Mon Sep 17 00:00:00 2001 From: David Daney Date: Wed, 24 May 2017 16:35:49 -0700 Subject: test_bpf: Add a couple of tests for BPF_JSGE. Some JITs can optimize comparisons with zero. Add a couple of BPF_JSGE tests against immediate zero. Signed-off-by: David Daney Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- lib/test_bpf.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'lib') diff --git a/lib/test_bpf.c b/lib/test_bpf.c index 889bc31785be..be88cbaadde3 100644 --- a/lib/test_bpf.c +++ b/lib/test_bpf.c @@ -4504,6 +4504,44 @@ static struct bpf_test tests[] = { { }, { { 0, 1 } }, }, + { + "JMP_JSGE_K: Signed jump: value walk 1", + .u.insns_int = { + BPF_ALU32_IMM(BPF_MOV, R0, 0), + BPF_LD_IMM64(R1, -3), + BPF_JMP_IMM(BPF_JSGE, R1, 0, 6), + BPF_ALU64_IMM(BPF_ADD, R1, 1), + BPF_JMP_IMM(BPF_JSGE, R1, 0, 4), + BPF_ALU64_IMM(BPF_ADD, R1, 1), + BPF_JMP_IMM(BPF_JSGE, R1, 0, 2), + BPF_ALU64_IMM(BPF_ADD, R1, 1), + BPF_JMP_IMM(BPF_JSGE, R1, 0, 1), + BPF_EXIT_INSN(), /* bad exit */ + BPF_ALU32_IMM(BPF_MOV, R0, 1), /* good exit */ + BPF_EXIT_INSN(), + }, + INTERNAL, + { }, + { { 0, 1 } }, + }, + { + "JMP_JSGE_K: Signed jump: value walk 2", + .u.insns_int = { + BPF_ALU32_IMM(BPF_MOV, R0, 0), + BPF_LD_IMM64(R1, -3), + BPF_JMP_IMM(BPF_JSGE, R1, 0, 4), + BPF_ALU64_IMM(BPF_ADD, R1, 2), + BPF_JMP_IMM(BPF_JSGE, R1, 0, 2), + BPF_ALU64_IMM(BPF_ADD, R1, 2), + BPF_JMP_IMM(BPF_JSGE, R1, 0, 1), + BPF_EXIT_INSN(), /* bad exit */ + BPF_ALU32_IMM(BPF_MOV, R0, 1), /* good exit */ + BPF_EXIT_INSN(), + }, + INTERNAL, + { }, + { { 0, 1 } }, + }, /* BPF_JMP | BPF_JGT | BPF_K */ { "JMP_JGT_K: if (3 > 2) return 1", -- cgit v1.2.3-59-g8ed1b From d41519a69b35b10af7fda867fb9100df24fdf403 Mon Sep 17 00:00:00 2001 From: David Miller Date: Fri, 2 Jun 2017 11:28:54 -0400 Subject: crypto: Work around deallocated stack frame reference gcc bug on sparc. On sparc, if we have an alloca() like situation, as is the case with SHASH_DESC_ON_STACK(), we can end up referencing deallocated stack memory. The result can be that the value is clobbered if a trap or interrupt arrives at just the right instruction. It only occurs if the function ends returning a value from that alloca() area and that value can be placed into the return value register using a single instruction. For example, in lib/libcrc32c.c:crc32c() we end up with a return sequence like: return %i7+8 lduw [%o5+16], %o0 ! MEM[(u32 *)__shash_desc.1_10 + 16B], %o5 holds the base of the on-stack area allocated for the shash descriptor. But the return released the stack frame and the register window. So if an intererupt arrives between 'return' and 'lduw', then the value read at %o5+16 can be corrupted. Add a data compiler barrier to work around this problem. This is exactly what the gcc fix will end up doing as well, and it absolutely should not change the code generated for other cpus (unless gcc on them has the same bug :-) With crucial insight from Eric Sandeen. Cc: Reported-by: Anatoly Pugachev Signed-off-by: David S. Miller Signed-off-by: Herbert Xu --- drivers/infiniband/sw/rxe/rxe.h | 5 ++++- fs/btrfs/hash.c | 5 ++++- fs/f2fs/f2fs.h | 5 ++++- lib/libcrc32c.c | 6 ++++-- 4 files changed, 16 insertions(+), 5 deletions(-) (limited to 'lib') diff --git a/drivers/infiniband/sw/rxe/rxe.h b/drivers/infiniband/sw/rxe/rxe.h index ecdba2fce083..1ac5b8551a4d 100644 --- a/drivers/infiniband/sw/rxe/rxe.h +++ b/drivers/infiniband/sw/rxe/rxe.h @@ -68,6 +68,7 @@ static inline u32 rxe_crc32(struct rxe_dev *rxe, u32 crc, void *next, size_t len) { + u32 retval; int err; SHASH_DESC_ON_STACK(shash, rxe->tfm); @@ -81,7 +82,9 @@ static inline u32 rxe_crc32(struct rxe_dev *rxe, return crc32_le(crc, next, len); } - return *(u32 *)shash_desc_ctx(shash); + retval = *(u32 *)shash_desc_ctx(shash); + barrier_data(shash_desc_ctx(shash)); + return retval; } int rxe_set_mtu(struct rxe_dev *rxe, unsigned int dev_mtu); diff --git a/fs/btrfs/hash.c b/fs/btrfs/hash.c index a97fdc156a03..baacc1866861 100644 --- a/fs/btrfs/hash.c +++ b/fs/btrfs/hash.c @@ -38,6 +38,7 @@ u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length) { SHASH_DESC_ON_STACK(shash, tfm); u32 *ctx = (u32 *)shash_desc_ctx(shash); + u32 retval; int err; shash->tfm = tfm; @@ -47,5 +48,7 @@ u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length) err = crypto_shash_update(shash, address, length); BUG_ON(err); - return *ctx; + retval = *ctx; + barrier_data(ctx); + return retval; } diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 2185c7a040a1..fd2e651bad6d 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -1078,6 +1078,7 @@ static inline u32 f2fs_crc32(struct f2fs_sb_info *sbi, const void *address, { SHASH_DESC_ON_STACK(shash, sbi->s_chksum_driver); u32 *ctx = (u32 *)shash_desc_ctx(shash); + u32 retval; int err; shash->tfm = sbi->s_chksum_driver; @@ -1087,7 +1088,9 @@ static inline u32 f2fs_crc32(struct f2fs_sb_info *sbi, const void *address, err = crypto_shash_update(shash, address, length); BUG_ON(err); - return *ctx; + retval = *ctx; + barrier_data(ctx); + return retval; } static inline bool f2fs_crc_valid(struct f2fs_sb_info *sbi, __u32 blk_crc, diff --git a/lib/libcrc32c.c b/lib/libcrc32c.c index 74a54b7f2562..9f79547d1b97 100644 --- a/lib/libcrc32c.c +++ b/lib/libcrc32c.c @@ -43,7 +43,7 @@ static struct crypto_shash *tfm; u32 crc32c(u32 crc, const void *address, unsigned int length) { SHASH_DESC_ON_STACK(shash, tfm); - u32 *ctx = (u32 *)shash_desc_ctx(shash); + u32 ret, *ctx = (u32 *)shash_desc_ctx(shash); int err; shash->tfm = tfm; @@ -53,7 +53,9 @@ u32 crc32c(u32 crc, const void *address, unsigned int length) err = crypto_shash_update(shash, address, length); BUG_ON(err); - return *ctx; + ret = *ctx; + barrier_data(ctx); + return ret; } EXPORT_SYMBOL(crc32c); -- cgit v1.2.3-59-g8ed1b