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authorJan Kara <jack@suse.cz>2014-08-17 11:49:57 +0200
committerJan Kara <jack@suse.cz>2014-08-19 18:29:30 +0200
commit410dd3cf4c9b36f27ed4542ee18b1af5e68645a4 (patch)
treebe3af2da6fcc9bd0ef2518e6d344d726670b2df7 /fs/isofs/rock.c
parentudf: avoid unneeded up_write when fail to add entry in ->symlink (diff)
downloadlinux-410dd3cf4c9b36f27ed4542ee18b1af5e68645a4.tar.xz
linux-410dd3cf4c9b36f27ed4542ee18b1af5e68645a4.zip
isofs: Fix unbounded recursion when processing relocated directories
We did not check relocated directory in any way when processing Rock Ridge 'CL' tag. Thus a corrupted isofs image can possibly have a CL entry pointing to another CL entry leading to possibly unbounded recursion in kernel code and thus stack overflow or deadlocks (if there is a loop created from CL entries). Fix the problem by not allowing CL entry to point to a directory entry with CL entry (such use makes no good sense anyway) and by checking whether CL entry doesn't point to itself. CC: stable@vger.kernel.org Reported-by: Chris Evans <cevans@google.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/isofs/rock.c')
-rw-r--r--fs/isofs/rock.c39
1 files changed, 28 insertions, 11 deletions
diff --git a/fs/isofs/rock.c b/fs/isofs/rock.c
index c0bf42472e40..f488bbae541a 100644
--- a/fs/isofs/rock.c
+++ b/fs/isofs/rock.c
@@ -288,12 +288,16 @@ eio:
goto out;
}
+#define RR_REGARD_XA 1
+#define RR_RELOC_DE 2
+
static int
parse_rock_ridge_inode_internal(struct iso_directory_record *de,
- struct inode *inode, int regard_xa)
+ struct inode *inode, int flags)
{
int symlink_len = 0;
int cnt, sig;
+ unsigned int reloc_block;
struct inode *reloc;
struct rock_ridge *rr;
int rootflag;
@@ -305,7 +309,7 @@ parse_rock_ridge_inode_internal(struct iso_directory_record *de,
init_rock_state(&rs, inode);
setup_rock_ridge(de, inode, &rs);
- if (regard_xa) {
+ if (flags & RR_REGARD_XA) {
rs.chr += 14;
rs.len -= 14;
if (rs.len < 0)
@@ -485,12 +489,22 @@ repeat:
"relocated directory\n");
goto out;
case SIG('C', 'L'):
- ISOFS_I(inode)->i_first_extent =
- isonum_733(rr->u.CL.location);
- reloc =
- isofs_iget(inode->i_sb,
- ISOFS_I(inode)->i_first_extent,
- 0);
+ if (flags & RR_RELOC_DE) {
+ printk(KERN_ERR
+ "ISOFS: Recursive directory relocation "
+ "is not supported\n");
+ goto eio;
+ }
+ reloc_block = isonum_733(rr->u.CL.location);
+ if (reloc_block == ISOFS_I(inode)->i_iget5_block &&
+ ISOFS_I(inode)->i_iget5_offset == 0) {
+ printk(KERN_ERR
+ "ISOFS: Directory relocation points to "
+ "itself\n");
+ goto eio;
+ }
+ ISOFS_I(inode)->i_first_extent = reloc_block;
+ reloc = isofs_iget_reloc(inode->i_sb, reloc_block, 0);
if (IS_ERR(reloc)) {
ret = PTR_ERR(reloc);
goto out;
@@ -637,9 +651,11 @@ static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit)
return rpnt;
}
-int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode)
+int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode,
+ int relocated)
{
- int result = parse_rock_ridge_inode_internal(de, inode, 0);
+ int flags = relocated ? RR_RELOC_DE : 0;
+ int result = parse_rock_ridge_inode_internal(de, inode, flags);
/*
* if rockridge flag was reset and we didn't look for attributes
@@ -647,7 +663,8 @@ int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode)
*/
if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1)
&& (ISOFS_SB(inode->i_sb)->s_rock == 2)) {
- result = parse_rock_ridge_inode_internal(de, inode, 14);
+ result = parse_rock_ridge_inode_internal(de, inode,
+ flags | RR_REGARD_XA);
}
return result;
}