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| author | John Ogness <john.ogness@linutronix.de> | 2020-09-30 11:01:33 +0200 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2020-09-30 13:30:28 +0200 |
| commit | 59f8bcca1ef6a5326f7c127e11b949e745bfa230 (patch) | |
| tree | 52d947f428b834079aa907ec10be9967376ab5a8 /kernel/printk/printk_ringbuffer.h | |
| parent | printk: remove dict ring (diff) | |
| download | linux-59f8bcca1ef6a5326f7c127e11b949e745bfa230.tar.xz linux-59f8bcca1ef6a5326f7c127e11b949e745bfa230.zip | |
printk: avoid and/or handle record truncation
If a reader provides a buffer that is smaller than the message text,
the @text_len field of @info will have a value larger than the buffer
size. If readers blindly read @text_len bytes of data without
checking the size, they will read beyond their buffer.
Add this check to record_print_text() to properly recognize when such
truncation has occurred.
Add a maximum size argument to the ringbuffer function to extend
records so that records can not be created that are larger than the
buffer size of readers.
When extending records (LOG_CONT), do not extend records beyond
LOG_LINE_MAX since that is the maximum size available in the buffers
used by consoles and syslog.
Fixes: f5f022e53b87 ("printk: reimplement log_cont using record extension")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200930090134.8723-2-john.ogness@linutronix.de
Diffstat (limited to 'kernel/printk/printk_ringbuffer.h')
| -rw-r--r-- | kernel/printk/printk_ringbuffer.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/printk/printk_ringbuffer.h b/kernel/printk/printk_ringbuffer.h index 0adaa685d1ca..5dc9d022db07 100644 --- a/kernel/printk/printk_ringbuffer.h +++ b/kernel/printk/printk_ringbuffer.h @@ -303,7 +303,7 @@ static inline void prb_rec_init_wr(struct printk_record *r, bool prb_reserve(struct prb_reserved_entry *e, struct printk_ringbuffer *rb, struct printk_record *r); bool prb_reserve_in_last(struct prb_reserved_entry *e, struct printk_ringbuffer *rb, - struct printk_record *r, u32 caller_id); + struct printk_record *r, u32 caller_id, unsigned int max_size); void prb_commit(struct prb_reserved_entry *e); void prb_final_commit(struct prb_reserved_entry *e); |