perf_counter: buffer overwrite problem for perf top command

perf_counter: buffer overwrite problem for perf top command

[Erdem Aktas]

Hi;
There is a buffer overwrite problem in builtin-top.c line 526, When I
tried to use ./perf top command, it was giving memory corruption
problem. should not we use malloc(strlen(str)+1) ?

Regards
-erdem


=======================
diff --git a/Documentation/perf_counter/builtin-top.c
b/Documentation/perf_counter/builtin-top.c
index cd6f61d..b1549dd 100644
--- a/Documentation/perf_counter/builtin-top.c
+++ b/Documentation/perf_counter/builtin-top.c
@@ -523,7 +523,7 @@ static int read_symbol(FILE *in, struct sym_entry *s)
 	if (strstr(sym, "_text_start") || strstr(sym, "_text_end"))
 		return 1;

-	s->sym = malloc(strlen(str));
+	s->sym = malloc(strlen(str)+1);
 	assert(s->sym);

 	strcpy((char *)s->sym, str);

Re: perf_counter: buffer overwrite problem for perf top command

[Ingo Molnar]

* Erdem Aktas <eaktas1@gmail.com> wrote:

> Hi;
> There is a buffer overwrite problem in builtin-top.c line 526, When I
> tried to use ./perf top command, it was giving memory corruption
> problem. should not we use malloc(strlen(str)+1) ?

indeed, well spotted - we do an strcpy into that buffer so the \0 at 
the end of the string has to be allocated too.

I've applied it to tip:perfcounters/core and tip/master and pushed 
it out. Thanks,

	Ingo

[tip:perfcounters/core] perf_counter tools: fix buffer overwrite problem for perf top command

[tip-bot for Erdem Aktas]

Commit-ID:  82afae6016b672acb90ceb8e773bba0bd977d2a3
Gitweb:     http://git.kernel.org/tip/82afae6016b672acb90ceb8e773bba0bd977d2a3
Author:     Erdem Aktas <eaktas1@gmail.com>
AuthorDate: Sun, 10 May 2009 02:13:19 -0400
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Sun, 10 May 2009 08:21:18 +0200

perf_counter tools: fix buffer overwrite problem for perf top command

There is a buffer overwrite problem in builtin-top.c line 526, When I
tried to use ./perf top command, it was giving memory corruption
problem.

[ Impact: fix 'perf top' crash ]

LKML-Reference: <3fee128b0905092313x608e65e0l7b1116d86914114f@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
 Documentation/perf_counter/builtin-top.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/Documentation/perf_counter/builtin-top.c b/Documentation/perf_counter/builtin-top.c
index cd6f61d..b1549dd 100644
--- a/Documentation/perf_counter/builtin-top.c
+++ b/Documentation/perf_counter/builtin-top.c
@@ -523,7 +523,7 @@ static int read_symbol(FILE *in, struct sym_entry *s)
 	if (strstr(sym, "_text_start") || strstr(sym, "_text_end"))
 		return 1;
 
-	s->sym = malloc(strlen(str));
+	s->sym = malloc(strlen(str)+1);
 	assert(s->sym);
 
 	strcpy((char *)s->sym, str);