diff options
| author | Robert Richter <robert.richter@amd.com> | 2011-12-19 16:38:30 +0100 |
|---|---|---|
| committer | Rohan Somvanshi <rsomvanshi@nvidia.com> | 2012-01-11 09:30:03 -0800 |
| commit | f29e1d17465957646fb135f1032f8aa7b5e8aeaf (patch) | |
| tree | 3dfcf3077d3e3af05ef5b28848cb76eefdce0ac5 /arch/s390 | |
| parent | b42e9d1709655fb4fcea049f1766122b8cf3c6cb (diff) | |
oprofile: Fix uninitialized memory access when writing to writing to oprofilefs
commit 913050b91eb94f194392dd797b1ff3779f606ac0 upstream.
If oprofilefs_ulong_from_user() is called with count equals
zero, *val remains unchanged. Depending on the implementation it
might be uninitialized.
Change oprofilefs_ulong_from_user()'s interface to return count
on success. Thus, we are able to return early if count equals
zero which avoids using *val uninitialized. Fixing all users of
oprofilefs_ulong_ from_user().
This follows write syscall implementation when count is zero:
"If count is zero ... [and if] no errors are detected, 0 will be
returned without causing any other effect." (man 2 write)
Reported-By: Mike Waychison <mikew@google.com>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: oprofile-list <oprofile-list@lists.sourceforge.net>
Link: http://lkml.kernel.org/r/20111219153830.GH16765@erda.amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Change-Id: Ic9b5dd12ec6e93b609b0e61acd02944352cd436d
Reviewed-on: http://git-master/r/74177
Reviewed-by: Varun Wadekar <vwadekar@nvidia.com>
Tested-by: Varun Wadekar <vwadekar@nvidia.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/oprofile/init.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/s390/oprofile/init.c b/arch/s390/oprofile/init.c index 6efc18b5e60a..bd58b72454cf 100644 --- a/arch/s390/oprofile/init.c +++ b/arch/s390/oprofile/init.c @@ -88,7 +88,7 @@ static ssize_t hwsampler_write(struct file *file, char const __user *buf, return -EINVAL; retval = oprofilefs_ulong_from_user(&val, buf, count); - if (retval) + if (retval <= 0) return retval; if (oprofile_started) |