diff options
| author | Jan Kara <jack@suse.cz> | 2014-08-17 13:49:57 +0400 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2014-08-19 20:29:30 +0400 |
| commit | 410dd3cf4c9b36f27ed4542ee18b1af5e68645a4 (patch) | |
| tree | be3af2da6fcc9bd0ef2518e6d344d726670b2df7 /fs/isofs/rock.c | |
| parent | 85cd083b498572fb9fa575cce3ed910c8ee84294 (diff) | |
| download | linux-410dd3cf4c9b36f27ed4542ee18b1af5e68645a4.tar.xz | |
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.c | 39 |
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; } |