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authorRobert Richter <robert.richter@amd.com>2011-12-19 16:38:30 +0100
committerIngo Molnar <mingo@elte.hu>2011-12-19 17:18:43 +0100
commit913050b91eb94f194392dd797b1ff3779f606ac0 (patch)
treebcb861e17dc40875ef0f694641392b7177f04852 /arch/s390/oprofile
parent497f16f21a04060098c0da6ed522fbcafb90c0db (diff)
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/oprofile')
-rw-r--r--arch/s390/oprofile/init.c2
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)