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| author | Kees Cook <keescook@chromium.org> | 2023-08-10 22:45:32 -0700 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2023-08-14 13:05:22 +0200 |
| commit | 53e9e33ede37a247d926db5e4a9e56b55204e66c (patch) | |
| tree | ed369146574085fecd752919ec0a7bec0d7b874e /kernel | |
| parent | cd47fe860185a8d385bba693ab79497fdf12cd78 (diff) | |
| download | linux-53e9e33ede37a247d926db5e4a9e56b55204e66c.tar.gz linux-53e9e33ede37a247d926db5e4a9e56b55204e66c.tar.bz2 linux-53e9e33ede37a247d926db5e4a9e56b55204e66c.zip | |
printk: ringbuffer: Fix truncating buffer size min_t cast
If an output buffer size exceeded U16_MAX, the min_t(u16, ...) cast in
copy_data() was causing writes to truncate. This manifested as output
bytes being skipped, seen as %NUL bytes in pstore dumps when the available
record size was larger than 65536. Fix the cast to no longer truncate
the calculation.
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Ogness <john.ogness@linutronix.de>
Reported-by: Vijay Balakrishna <vijayb@linux.microsoft.com>
Link: https://lore.kernel.org/lkml/d8bb1ec7-a4c5-43a2-9de0-9643a70b899f@linux.microsoft.com/
Fixes: b6cf8b3f3312 ("printk: add lockless ringbuffer")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Vijay Balakrishna <vijayb@linux.microsoft.com>
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Reviewed-by: Tyler Hicks (Microsoft) <code@tyhicks.com>
Tested-by: Tyler Hicks (Microsoft) <code@tyhicks.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230811054528.never.165-kees@kernel.org
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/printk/printk_ringbuffer.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c index 2dc4d5a1f1ff..fde338606ce8 100644 --- a/kernel/printk/printk_ringbuffer.c +++ b/kernel/printk/printk_ringbuffer.c @@ -1735,7 +1735,7 @@ static bool copy_data(struct prb_data_ring *data_ring, if (!buf || !buf_size) return true; - data_size = min_t(u16, buf_size, len); + data_size = min_t(unsigned int, buf_size, len); memcpy(&buf[0], data, data_size); /* LMM(copy_data:A) */ return true; |