|
 |
ad8337e |
From a45318b5ff8c505afcbf04a1c5fa7dbe426d9588 Mon Sep 17 00:00:00 2001
|
|
|
ad8337e |
From: Jan Kara <jack@suse.cz>
|
|
|
ad8337e |
Date: Thu, 4 Sep 2014 14:06:55 +0200
|
|
|
ad8337e |
Subject: [PATCH] udf: Avoid infinite loop when processing indirect ICBs
|
|
|
ad8337e |
|
|
|
ad8337e |
We did not implement any bound on number of indirect ICBs we follow when
|
|
|
ad8337e |
loading inode. Thus corrupted medium could cause kernel to go into an
|
|
|
ad8337e |
infinite loop, possibly causing a stack overflow.
|
|
|
ad8337e |
|
|
|
ad8337e |
Fix the possible stack overflow by removing recursion from
|
|
|
ad8337e |
__udf_read_inode() and limit number of indirect ICBs we follow to avoid
|
|
|
ad8337e |
infinite loops.
|
|
|
ad8337e |
|
|
|
ad8337e |
Bugzilla: 1141810
|
|
|
ad8337e |
Upstream-status: 3.17
|
|
|
ad8337e |
|
|
|
ad8337e |
Signed-off-by: Jan Kara <jack@suse.cz>
|
|
|
ad8337e |
---
|
|
|
ad8337e |
fs/udf/inode.c | 35 +++++++++++++++++++++--------------
|
|
|
ad8337e |
1 file changed, 21 insertions(+), 14 deletions(-)
|
|
|
ad8337e |
|
|
|
ad8337e |
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
|
|
|
ad8337e |
index 236cd48184c2..a932f7740b51 100644
|
|
|
ad8337e |
--- a/fs/udf/inode.c
|
|
|
ad8337e |
+++ b/fs/udf/inode.c
|
|
|
ad8337e |
@@ -1271,13 +1271,22 @@ update_time:
|
|
|
ad8337e |
return 0;
|
|
|
ad8337e |
}
|
|
|
ad8337e |
|
|
|
ad8337e |
+/*
|
|
|
ad8337e |
+ * Maximum length of linked list formed by ICB hierarchy. The chosen number is
|
|
|
ad8337e |
+ * arbitrary - just that we hopefully don't limit any real use of rewritten
|
|
|
ad8337e |
+ * inode on write-once media but avoid looping for too long on corrupted media.
|
|
|
ad8337e |
+ */
|
|
|
ad8337e |
+#define UDF_MAX_ICB_NESTING 1024
|
|
|
ad8337e |
+
|
|
|
ad8337e |
static void __udf_read_inode(struct inode *inode)
|
|
|
ad8337e |
{
|
|
|
ad8337e |
struct buffer_head *bh = NULL;
|
|
|
ad8337e |
struct fileEntry *fe;
|
|
|
ad8337e |
uint16_t ident;
|
|
|
ad8337e |
struct udf_inode_info *iinfo = UDF_I(inode);
|
|
|
ad8337e |
+ unsigned int indirections = 0;
|
|
|
ad8337e |
|
|
|
ad8337e |
+reread:
|
|
|
ad8337e |
/*
|
|
|
ad8337e |
* Set defaults, but the inode is still incomplete!
|
|
|
ad8337e |
* Note: get_new_inode() sets the following on a new inode:
|
|
|
ad8337e |
@@ -1314,28 +1323,26 @@ static void __udf_read_inode(struct inode *inode)
|
|
|
ad8337e |
ibh = udf_read_ptagged(inode->i_sb, &iinfo->i_location, 1,
|
|
|
ad8337e |
&ident);
|
|
|
ad8337e |
if (ident == TAG_IDENT_IE && ibh) {
|
|
|
ad8337e |
- struct buffer_head *nbh = NULL;
|
|
|
ad8337e |
struct kernel_lb_addr loc;
|
|
|
ad8337e |
struct indirectEntry *ie;
|
|
|
ad8337e |
|
|
|
ad8337e |
ie = (struct indirectEntry *)ibh->b_data;
|
|
|
ad8337e |
loc = lelb_to_cpu(ie->indirectICB.extLocation);
|
|
|
ad8337e |
|
|
|
ad8337e |
- if (ie->indirectICB.extLength &&
|
|
|
ad8337e |
- (nbh = udf_read_ptagged(inode->i_sb, &loc, 0,
|
|
|
ad8337e |
- &ident))) {
|
|
|
ad8337e |
- if (ident == TAG_IDENT_FE ||
|
|
|
ad8337e |
- ident == TAG_IDENT_EFE) {
|
|
|
ad8337e |
- memcpy(&iinfo->i_location,
|
|
|
ad8337e |
- &loc,
|
|
|
ad8337e |
- sizeof(struct kernel_lb_addr));
|
|
|
ad8337e |
- brelse(bh);
|
|
|
ad8337e |
- brelse(ibh);
|
|
|
ad8337e |
- brelse(nbh);
|
|
|
ad8337e |
- __udf_read_inode(inode);
|
|
|
ad8337e |
+ if (ie->indirectICB.extLength) {
|
|
|
ad8337e |
+ brelse(bh);
|
|
|
ad8337e |
+ brelse(ibh);
|
|
|
ad8337e |
+ memcpy(&iinfo->i_location, &loc,
|
|
|
ad8337e |
+ sizeof(struct kernel_lb_addr));
|
|
|
ad8337e |
+ if (++indirections > UDF_MAX_ICB_NESTING) {
|
|
|
ad8337e |
+ udf_err(inode->i_sb,
|
|
|
ad8337e |
+ "too many ICBs in ICB hierarchy"
|
|
|
ad8337e |
+ " (max %d supported)\n",
|
|
|
ad8337e |
+ UDF_MAX_ICB_NESTING);
|
|
|
ad8337e |
+ make_bad_inode(inode);
|
|
|
ad8337e |
return;
|
|
|
ad8337e |
}
|
|
|
ad8337e |
- brelse(nbh);
|
|
|
ad8337e |
+ goto reread;
|
|
|
ad8337e |
}
|
|
|
ad8337e |
}
|
|
|
ad8337e |
brelse(ibh);
|
|
|
ad8337e |
--
|
|
|
ad8337e |
2.1.0
|
|
|
ad8337e |
|