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authorAravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>2015-10-12 11:22:38 +0200
committerIngo Molnar <mingo@kernel.org>2015-10-12 16:15:47 +0200
commit85c9306d44f757d2fb3b0e3e399080a025315c7f (patch)
treef3739ff23a559c7370e6a578edbde3daad2e3c5a /arch/x86/ras
parentcdbcd239e2e264dc3ef7bc7865bcb8ec0023876f (diff)
downloadlinux-85c9306d44f757d2fb3b0e3e399080a025315c7f.tar.bz2
x86/ras/mce_amd_inj: Return early on invalid input
Invalid inputs such as these are currently reported in dmesg as failing: $> echo sweet > flags [ 122.079139] flags_write: Invalid flags value: et even though the 'flags' attribute has been updated correctly: $> cat flags sw This is because userspace keeps writing the remaining buffer until it encounters an error. However, the input as a whole is wrong and we should not be writing anything to the file. Therefore, correct flags_write() to return -EINVAL immediately on bad input strings. Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/1443190851-2172-2-git-send-email-Aravind.Gopalakrishnan@amd.com Link: http://lkml.kernel.org/r/1444641762-9437-3-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/ras')
-rw-r--r--arch/x86/ras/mce_amd_inj.c9
1 files changed, 3 insertions, 6 deletions
diff --git a/arch/x86/ras/mce_amd_inj.c b/arch/x86/ras/mce_amd_inj.c
index 17e35b5bf779..4fd8bb9b90b9 100644
--- a/arch/x86/ras/mce_amd_inj.c
+++ b/arch/x86/ras/mce_amd_inj.c
@@ -129,12 +129,9 @@ static ssize_t flags_write(struct file *filp, const char __user *ubuf,
{
char buf[MAX_FLAG_OPT_SIZE], *__buf;
int err;
- size_t ret;
if (cnt > MAX_FLAG_OPT_SIZE)
- cnt = MAX_FLAG_OPT_SIZE;
-
- ret = cnt;
+ return -EINVAL;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
@@ -150,9 +147,9 @@ static ssize_t flags_write(struct file *filp, const char __user *ubuf,
return err;
}
- *ppos += ret;
+ *ppos += cnt;
- return ret;
+ return cnt;
}
static const struct file_operations flags_fops = {