| From | Greg Kroah-Hartman <> | Subject | [ 111/171] libceph: fix overflow in __decode_pool_names() | Date | Wed, 21 Nov 2012 16:40:57 -0800 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Xi Wang <xi.wang@gmail.com>
(cherry picked from commit ad3b904c07dfa88603689bf9a67bffbb9b99beb5)
`len' is read from network and thus needs validation. Otherwise a large `len' would cause out-of-bounds access via the memcpy() call. In addition, len = 0xffffffff would overflow the kmalloc() size, leading to out-of-bounds write.
This patch adds a check of `len' via ceph_decode_need(). Also use kstrndup rather than kmalloc/memcpy.
[elder@inktank.com: added -ENOMEM return for null kstrndup() result]
Signed-off-by: Xi Wang <xi.wang@gmail.com> Reviewed-by: Alex Elder <elder@inktank.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/ceph/osdmap.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
--- a/net/ceph/osdmap.c +++ b/net/ceph/osdmap.c @@ -495,15 +495,16 @@ static int __decode_pool_names(void **p, ceph_decode_32_safe(p, end, pool, bad); ceph_decode_32_safe(p, end, len, bad); dout(" pool %d len %d\n", pool, len); + ceph_decode_need(p, end, len, bad); pi = __lookup_pg_pool(&map->pg_pools, pool); if (pi) { + char *name = kstrndup(*p, len, GFP_NOFS); + + if (!name) + return -ENOMEM; kfree(pi->name); - pi->name = kmalloc(len + 1, GFP_NOFS); - if (pi->name) { - memcpy(pi->name, *p, len); - pi->name[len] = '\0'; - dout(" name is %s\n", pi->name); - } + pi->name = name; + dout(" name is %s\n", pi->name); } *p += len; }
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