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author | David S. Miller <davem@davemloft.net> | 2015-08-28 16:27:28 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2015-08-28 16:27:28 -0700 |
commit | cc7acad135b7228b56977867afb07d3d54f0cdd3 (patch) | |
tree | 8934c8b0f6aac4a01488c59c45b8dc55c64cc721 /kernel | |
parent | netpoll: warn on netpoll_send_udp users who haven't disabled irqs (diff) | |
parent | bpf: add support for %s specifier to bpf_trace_printk() (diff) | |
download | linux-dev-cc7acad135b7228b56977867afb07d3d54f0cdd3.tar.xz linux-dev-cc7acad135b7228b56977867afb07d3d54f0cdd3.zip |
Merge branch 'bpf_trace_printk-percent-s'
Alexei Starovoitov says:
====================
support for '%s' in bpf_trace_printk
v2->v3:
fix the comment to mention that strncpy_from_unsafe() returns
the length of the string including the trailing NUL.
v1->v2:
patch 1: generalize FETCH_FUNC_NAME(memory, string) into
strncpy_from_unsafe()
patch 2: use it in bpf_trace_printk
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/trace/bpf_trace.c | 32 | ||||
-rw-r--r-- | kernel/trace/trace_kprobe.c | 20 |
2 files changed, 34 insertions, 18 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index ef9936df1b04..0fe96c7c8803 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -81,13 +81,16 @@ static const struct bpf_func_proto bpf_probe_read_proto = { /* * limited trace_printk() - * only %d %u %x %ld %lu %lx %lld %llu %llx %p conversion specifiers allowed + * only %d %u %x %ld %lu %lx %lld %llu %llx %p %s conversion specifiers allowed */ static u64 bpf_trace_printk(u64 r1, u64 fmt_size, u64 r3, u64 r4, u64 r5) { char *fmt = (char *) (long) r1; + bool str_seen = false; int mod[3] = {}; int fmt_cnt = 0; + u64 unsafe_addr; + char buf[64]; int i; /* @@ -114,12 +117,37 @@ static u64 bpf_trace_printk(u64 r1, u64 fmt_size, u64 r3, u64 r4, u64 r5) if (fmt[i] == 'l') { mod[fmt_cnt]++; i++; - } else if (fmt[i] == 'p') { + } else if (fmt[i] == 'p' || fmt[i] == 's') { mod[fmt_cnt]++; i++; if (!isspace(fmt[i]) && !ispunct(fmt[i]) && fmt[i] != 0) return -EINVAL; fmt_cnt++; + if (fmt[i - 1] == 's') { + if (str_seen) + /* allow only one '%s' per fmt string */ + return -EINVAL; + str_seen = true; + + switch (fmt_cnt) { + case 1: + unsafe_addr = r3; + r3 = (long) buf; + break; + case 2: + unsafe_addr = r4; + r4 = (long) buf; + break; + case 3: + unsafe_addr = r5; + r5 = (long) buf; + break; + } + buf[0] = 0; + strncpy_from_unsafe(buf, + (void *) (long) unsafe_addr, + sizeof(buf)); + } continue; } diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index b7d0cdd9906c..c9956440d0e6 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -165,11 +165,9 @@ DEFINE_BASIC_FETCH_FUNCS(memory) static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs, void *addr, void *dest) { - long ret; int maxlen = get_rloc_len(*(u32 *)dest); u8 *dst = get_rloc_data(dest); - u8 *src = addr; - mm_segment_t old_fs = get_fs(); + long ret; if (!maxlen) return; @@ -178,23 +176,13 @@ static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs, * Try to get string again, since the string can be changed while * probing. */ - set_fs(KERNEL_DS); - pagefault_disable(); - - do - ret = __copy_from_user_inatomic(dst++, src++, 1); - while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen); - - dst[-1] = '\0'; - pagefault_enable(); - set_fs(old_fs); + ret = strncpy_from_unsafe(dst, addr, maxlen); if (ret < 0) { /* Failed to fetch string */ - ((u8 *)get_rloc_data(dest))[0] = '\0'; + dst[0] = '\0'; *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest)); } else { - *(u32 *)dest = make_data_rloc(src - (u8 *)addr, - get_rloc_offs(*(u32 *)dest)); + *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest)); } } NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string)); |