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| author | Carl Henrik Lunde <chlunde@ping.uio.no> | 2009-04-03 16:27:15 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-04-03 16:46:22 +0400 |
| commit | a4b3ada83d06554d307dd54abdc62b2e5648264a (patch) | |
| tree | 70413a3343c8a40a8d3b22ec6d020ef806ca7a9b | |
| parent | 18cea4591a98817697017bcb056a848bae1205df (diff) | |
| download | linux-a4b3ada83d06554d307dd54abdc62b2e5648264a.tar.xz | |
blktrace: NUL-terminate user space messages
Impact: fix corrupted blkparse output
Make sure messages from user space are NUL-terminated strings,
otherwise we could dump random memory to the block trace file.
Additionally, I've limited the message to BLK_TN_MAX_MSG-1
characters, because the last character would be stripped by
vscnprintf anyway.
Signed-off-by: Carl Henrik Lunde <chlunde@ping.uio.no>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "Alan D. Brunelle" <alan.brunelle@hp.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20090403122714.GT5178@kernel.dk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/trace/blktrace.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 947c5b3f90c4..a400b861fad3 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -327,10 +327,10 @@ static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, char *msg; struct blk_trace *bt; - if (count > BLK_TN_MAX_MSG) + if (count > BLK_TN_MAX_MSG - 1) return -EINVAL; - msg = kmalloc(count, GFP_KERNEL); + msg = kmalloc(count + 1, GFP_KERNEL); if (msg == NULL) return -ENOMEM; @@ -339,6 +339,7 @@ static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, return -EFAULT; } + msg[count] = '\0'; bt = filp->private_data; __trace_note_message(bt, "%s", msg); kfree(msg); |