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| author | Zhang Zixun <zhang133010@icloud.com> | 2021-12-27 22:02:49 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-01-27 09:04:20 +0100 |
| commit | 6a706db05d9bb56d8c5463c2cf6ee7849b27c486 (patch) | |
| tree | 1236badaee30bd6c022ff391b7803a3a88cd43bb /arch | |
| parent | 27b198a8601a952383b6b64e1024621f63ba8fa8 (diff) | |
| download | linux-stable-6a706db05d9bb56d8c5463c2cf6ee7849b27c486.tar.gz linux-stable-6a706db05d9bb56d8c5463c2cf6ee7849b27c486.tar.bz2 linux-stable-6a706db05d9bb56d8c5463c2cf6ee7849b27c486.zip | |
x86/mce/inject: Avoid out-of-bounds write when setting flags
[ Upstream commit de768416b203ac84e02a757b782a32efb388476f ]
A contrived zero-length write, for example, by using write(2):
...
ret = write(fd, str, 0);
...
to the "flags" file causes:
BUG: KASAN: stack-out-of-bounds in flags_write
Write of size 1 at addr ffff888019be7ddf by task writefile/3787
CPU: 4 PID: 3787 Comm: writefile Not tainted 5.16.0-rc7+ #12
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
due to accessing buf one char before its start.
Prevent such out-of-bounds access.
[ bp: Productize into a proper patch. Link below is the next best
thing because the original mail didn't get archived on lore. ]
Fixes: 0451d14d0561 ("EDAC, mce_amd_inj: Modify flags attribute to use string arguments")
Signed-off-by: Zhang Zixun <zhang133010@icloud.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/linux-edac/YcnePfF1OOqoQwrX@zn.tnic/
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/mcheck/mce-inject.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/mcheck/mce-inject.c b/arch/x86/kernel/cpu/mcheck/mce-inject.c index 9cc524be3c94..14dc3c1f7fb4 100644 --- a/arch/x86/kernel/cpu/mcheck/mce-inject.c +++ b/arch/x86/kernel/cpu/mcheck/mce-inject.c @@ -354,7 +354,7 @@ static ssize_t flags_write(struct file *filp, const char __user *ubuf, char buf[MAX_FLAG_OPT_SIZE], *__buf; int err; - if (cnt > MAX_FLAG_OPT_SIZE) + if (!cnt || cnt > MAX_FLAG_OPT_SIZE) return -EINVAL; if (copy_from_user(&buf, ubuf, cnt)) |