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| author | Robert Richter <robert.richter@amd.com> | 2011-12-19 16:38:30 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-12-19 17:18:43 +0100 |
| commit | 913050b91eb94f194392dd797b1ff3779f606ac0 (patch) | |
| tree | bcb861e17dc40875ef0f694641392b7177f04852 /arch/s390 | |
| parent | 497f16f21a04060098c0da6ed522fbcafb90c0db (diff) | |
| download | lwn-913050b91eb94f194392dd797b1ff3779f606ac0.tar.gz lwn-913050b91eb94f194392dd797b1ff3779f606ac0.zip | |
oprofile: Fix uninitialized memory access when writing to writing to oprofilefs
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: <stable@vger.kernel.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>
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) |