From: Stian Skjelstad <stian.skjelstad@gmail.com> stable inclusion from linux-4.19.207 commit f08721ee2b387cc0ba93f8c27e2e3a6be80db2e4 -------------------------------- [ Upstream commit 58bc6d1be2f3b0ceecb6027dfa17513ec6aa2abb ] When parsing the ExtendedAttr data, malicous or corrupt attribute length could cause kernel hangs and buffer overruns in some special cases. Link: https://lore.kernel.org/r/20210822093332.25234-1-stian.skjelstad@gmail.com Signed-off-by: Stian Skjelstad <stian.skjelstad@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- fs/udf/misc.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/fs/udf/misc.c b/fs/udf/misc.c index 401e64cde1be0..853bcff51043f 100644 --- a/fs/udf/misc.c +++ b/fs/udf/misc.c @@ -173,13 +173,22 @@ struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type, else offset = le32_to_cpu(eahd->appAttrLocation); - while (offset < iinfo->i_lenEAttr) { + while (offset + sizeof(*gaf) < iinfo->i_lenEAttr) { + uint32_t attrLength; + gaf = (struct genericFormat *)&ea[offset]; + attrLength = le32_to_cpu(gaf->attrLength); + + /* Detect undersized elements and buffer overflows */ + if ((attrLength < sizeof(*gaf)) || + (attrLength > (iinfo->i_lenEAttr - offset))) + break; + if (le32_to_cpu(gaf->attrType) == type && gaf->attrSubtype == subtype) return gaf; else - offset += le32_to_cpu(gaf->attrLength); + offset += attrLength; } } -- 2.25.1