From: Vegard Nossum Date: Thu, 30 Jun 2016 15:53:46 +0000 (-0400) Subject: ext4: check for extents that wrap around X-Git-Tag: v3.2.84~144 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=acc016f68bf5fac0af3eeeb1b6f6dd7f97d58759;p=pandora-kernel.git ext4: check for extents that wrap around commit f70749ca42943faa4d4dcce46dfdcaadb1d0c4b6 upstream. An extent with lblock = 4294967295 and len = 1 will pass the ext4_valid_extent() test: ext4_lblk_t last = lblock + len - 1; if (len == 0 || lblock > last) return 0; since last = 4294967295 + 1 - 1 = 4294967295. This would later trigger the BUG_ON(es->es_lblk + es->es_len < es->es_lblk) in ext4_es_end(). We can simplify it by removing the - 1 altogether and changing the test to use lblock + len <= lblock, since now if len = 0, then lblock + 0 == lblock and it fails, and if len > 0 then lblock + len > lblock in order to pass (i.e. it doesn't overflow). Fixes: 5946d0893 ("ext4: check for overlapping extents in ext4_valid_extent_entries()") Fixes: 2f974865f ("ext4: check for zero length extent explicitly") Cc: Eryu Guan Signed-off-by: Phil Turnbull Signed-off-by: Vegard Nossum Signed-off-by: Theodore Ts'o Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed