Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.4 20/26] uml: check length in exitcode_proc_write() | Date | Fri, 8 Nov 2013 22:51:49 -0800 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Dan Carpenter <dan.carpenter@oracle.com>
commit 201f99f170df14ba52ea4c52847779042b7a623b upstream.
We don't cap the size of buffer from the user so we could write past the end of the array here. Only root can write to this file.
Reported-by: Nico Golde <nico@ngolde.de> Reported-by: Fabian Yamaguchi <fabs@goesec.de> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/um/kernel/exitcode.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/arch/um/kernel/exitcode.c +++ b/arch/um/kernel/exitcode.c @@ -40,9 +40,11 @@ static ssize_t exitcode_proc_write(struc const char __user *buffer, size_t count, loff_t *pos) { char *end, buf[sizeof("nnnnn\0")]; + size_t size; int tmp; - if (copy_from_user(buf, buffer, count)) + size = min(count, sizeof(buf)); + if (copy_from_user(buf, buffer, size)) return -EFAULT; tmp = simple_strtol(buf, &end, 0);
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