Messages in this thread Patch in this message | | | Date | Wed, 16 Dec 2009 19:55:52 -0800 | From | Greg KH <> | Subject | [055/151] hfs: fix a potential buffer overflow |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
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From: Amerigo Wang <amwang@redhat.com>
commit ec81aecb29668ad71f699f4e7b96ec46691895b6 upstream.
A specially-crafted Hierarchical File System (HFS) filesystem could cause a buffer overflow to occur in a process's kernel stack during a memcpy() call within the hfs_bnode_read() function (at fs/hfs/bnode.c:24). The attacker can provide the source buffer and length, and the destination buffer is a local variable of a fixed length. This local variable (passed as "&entry" from fs/hfs/dir.c:112 and allocated on line 60) is stored in the stack frame of hfs_bnode_read()'s caller, which is hfs_readdir(). Because the hfs_readdir() function executes upon any attempt to read a directory on the filesystem, it gets called whenever a user attempts to inspect any filesystem contents.
[amwang@redhat.com: modify this patch and fix coding style problems] Signed-off-by: WANG Cong <amwang@redhat.com> Cc: Eugene Teo <eteo@redhat.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Dave Anderson <anderson@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/hfs/catalog.c | 4 ++++ fs/hfs/dir.c | 11 +++++++++++ fs/hfs/super.c | 7 ++++++- 3 files changed, 21 insertions(+), 1 deletion(-)
--- a/fs/hfs/catalog.c +++ b/fs/hfs/catalog.c @@ -289,6 +289,10 @@ int hfs_cat_move(u32 cnid, struct inode err = hfs_brec_find(&src_fd); if (err) goto out; + if (src_fd.entrylength > sizeof(entry) || src_fd.entrylength < 0) { + err = -EIO; + goto out; + } hfs_bnode_read(src_fd.bnode, &entry, src_fd.entryoffset, src_fd.entrylength); --- a/fs/hfs/dir.c +++ b/fs/hfs/dir.c @@ -79,6 +79,11 @@ static int hfs_readdir(struct file *filp filp->f_pos++; /* fall through */ case 1: + if (fd.entrylength > sizeof(entry) || fd.entrylength < 0) { + err = -EIO; + goto out; + } + hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, fd.entrylength); if (entry.type != HFS_CDR_THD) { printk(KERN_ERR "hfs: bad catalog folder thread\n"); @@ -109,6 +114,12 @@ static int hfs_readdir(struct file *filp err = -EIO; goto out; } + + if (fd.entrylength > sizeof(entry) || fd.entrylength < 0) { + err = -EIO; + goto out; + } + hfs_bnode_read(fd.bnode, &entry, fd.entryoffset, fd.entrylength); type = entry.type; len = hfs_mac2asc(sb, strbuf, &fd.key->cat.CName); --- a/fs/hfs/super.c +++ b/fs/hfs/super.c @@ -409,8 +409,13 @@ static int hfs_fill_super(struct super_b /* try to get the root inode */ hfs_find_init(HFS_SB(sb)->cat_tree, &fd); res = hfs_cat_find_brec(sb, HFS_ROOT_CNID, &fd); - if (!res) + if (!res) { + if (fd.entrylength > sizeof(rec) || fd.entrylength < 0) { + res = -EIO; + goto bail; + } hfs_bnode_read(fd.bnode, &rec, fd.entryoffset, fd.entrylength); + } if (res) { hfs_find_exit(&fd); goto bail_no_root;
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