From 3ed02ada2a5e695e2fbb5e4a0008cfcb0f50feaa Mon Sep 17 00:00:00 2001 From: John Johansen Date: Sat, 9 Oct 2010 00:47:53 -0700 Subject: [PATCH] AppArmor: Ensure the size of the copy is < the buffer allocated to hold it Actually I think in this case the appropriate thing to do is to BUG as there is currently a case (remove) where the alloc_size needs to be larger than the copy_size, and if copy_size is ever greater than alloc_size there is a mistake in the caller code. Signed-off-by: John Johansen Acked-by: Kees Cook Signed-off-by: James Morris --- security/apparmor/apparmorfs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c index 7320331b44ab..544ff5837cb6 100644 --- a/security/apparmor/apparmorfs.c +++ b/security/apparmor/apparmorfs.c @@ -29,7 +29,7 @@ * aa_simple_write_to_buffer - common routine for getting policy from user * @op: operation doing the user buffer copy * @userbuf: user buffer to copy data from (NOT NULL) - * @alloc_size: size of user buffer + * @alloc_size: size of user buffer (REQUIRES: @alloc_size >= @copy_size) * @copy_size: size of data to copy from user buffer * @pos: position write is at in the file (NOT NULL) * @@ -42,6 +42,8 @@ static char *aa_simple_write_to_buffer(int op, const char __user *userbuf, { char *data; + BUG_ON(copy_size > alloc_size); + if (*pos != 0) /* only writes from pos 0, that is complete writes */ return ERR_PTR(-ESPIPE); -- 2.20.1