From 7ad74b41e56e4f7f42c6b765bc44428cd09310d7 Mon Sep 17 00:00:00 2001 From: Mitchell Krome Date: Tue, 16 Dec 2014 12:16:12 +1000 Subject: perf symbols: Fix use after free in filename__read_build_id In filename__read_build_id, phdr points to memory in buf, which gets realloced before a call to fseek that uses phdr->p_offset. This change stores the value of p_offset before buf is realloced, so the fseek can use the value safely. Signed-off-by: Mitchell Krome Cc: Jiri Olsa Cc: Ingo Molnar Cc: Jiri Olsa Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20141216021612.GA7199@mitchell Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/symbol-minimal.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'tools') diff --git a/tools/perf/util/symbol-minimal.c b/tools/perf/util/symbol-minimal.c index fa585c63f56a..d7efb03b3f9a 100644 --- a/tools/perf/util/symbol-minimal.c +++ b/tools/perf/util/symbol-minimal.c @@ -129,6 +129,7 @@ int filename__read_build_id(const char *filename, void *bf, size_t size) for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) { void *tmp; + long offset; if (need_swap) { phdr->p_type = bswap_32(phdr->p_type); @@ -140,12 +141,13 @@ int filename__read_build_id(const char *filename, void *bf, size_t size) continue; buf_size = phdr->p_filesz; + offset = phdr->p_offset; tmp = realloc(buf, buf_size); if (tmp == NULL) goto out_free; buf = tmp; - fseek(fp, phdr->p_offset, SEEK_SET); + fseek(fp, offset, SEEK_SET); if (fread(buf, buf_size, 1, fp) != 1) goto out_free; @@ -178,6 +180,7 @@ int filename__read_build_id(const char *filename, void *bf, size_t size) for (i = 0, phdr = buf; i < ehdr.e_phnum; i++, phdr++) { void *tmp; + long offset; if (need_swap) { phdr->p_type = bswap_32(phdr->p_type); @@ -189,12 +192,13 @@ int filename__read_build_id(const char *filename, void *bf, size_t size) continue; buf_size = phdr->p_filesz; + offset = phdr->p_offset; tmp = realloc(buf, buf_size); if (tmp == NULL) goto out_free; buf = tmp; - fseek(fp, phdr->p_offset, SEEK_SET); + fseek(fp, offset, SEEK_SET); if (fread(buf, buf_size, 1, fp) != 1) goto out_free; -- cgit v1.2.2