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author | Steven Rostedt (Red Hat) <rostedt@goodmis.org> | 2014-06-21 03:31:26 (GMT) |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2014-07-01 11:13:37 (GMT) |
commit | 6d2289f3faa71dcc5bba15c7aeba4f31c185b6df (patch) | |
tree | 8425f1195f29a670dcb1ad00e56ee1836514ab02 /kernel/trace/trace_seq.c | |
parent | 36aabfff50b6a03bcfd2c3cfbd7b83eb0a9ce0c1 (diff) | |
download | linux-6d2289f3faa71dcc5bba15c7aeba4f31c185b6df.tar.xz |
tracing: Make trace_seq_putmem_hex() more robust
Currently trace_seq_putmem_hex() can only take as a parameter a pointer
to something that is 8 bytes or less, otherwise it will overflow the
buffer. This is protected by a macro that encompasses the call to
trace_seq_putmem_hex() that has a BUILD_BUG_ON() for the variable before
it is passed in. This is not very robust and if trace_seq_putmem_hex() ever
gets used outside that macro it will cause issues.
Instead of only being able to produce a hex output of memory that is for
a single word, change it to be more robust and allow any size input.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_seq.c')
-rw-r--r-- | kernel/trace/trace_seq.c | 26 |
1 files changed, 19 insertions, 7 deletions
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c index 0fabca7..88c0f80 100644 --- a/kernel/trace/trace_seq.c +++ b/kernel/trace/trace_seq.c @@ -291,6 +291,7 @@ int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len) } EXPORT_SYMBOL_GPL(trace_seq_putmem); +#define MAX_MEMHEX_BYTES 8U #define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1) /** @@ -310,22 +311,33 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, { unsigned char hex[HEX_CHARS]; const unsigned char *data = mem; + unsigned int start_len; int i, j; + int cnt = 0; if (s->full) return 0; + while (len) { + start_len = min(len, HEX_CHARS - 1); #ifdef __BIG_ENDIAN - for (i = 0, j = 0; i < len; i++) { + for (i = 0, j = 0; i < start_len; i++) { #else - for (i = len-1, j = 0; i >= 0; i--) { + for (i = start_len-1, j = 0; i >= 0; i--) { #endif - hex[j++] = hex_asc_hi(data[i]); - hex[j++] = hex_asc_lo(data[i]); - } - hex[j++] = ' '; + hex[j++] = hex_asc_hi(data[i]); + hex[j++] = hex_asc_lo(data[i]); + } + if (WARN_ON_ONCE(j == 0 || j/2 > len)) + break; + + /* j increments twice per loop */ + len -= j / 2; + hex[j++] = ' '; - return trace_seq_putmem(s, hex, j); + cnt += trace_seq_putmem(s, hex, j); + } + return cnt; } EXPORT_SYMBOL_GPL(trace_seq_putmem_hex); |