Commit a4b3ada8 authored by Carl Henrik Lunde's avatar Carl Henrik Lunde Committed by Ingo Molnar

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: default avatarCarl 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: default avatarIngo Molnar <mingo@elte.hu>
parent 18cea459
......@@ -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);
......
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