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f37aa4c736
Sysbot has reported a number of "slab-out-of-bounds reads" and "use-after-free read" errors which has been identified as being caused by a corrupted index value read from the inode. This could be because the metadata block is uncompressed, or because the "compression" bit has been corrupted (turning a compressed block into an uncompressed block). This patch adds additional sanity checks to detect this, and the following corruption. 1. It checks against corruption of the ids count. This can either lead to a larger table to be read, or a smaller than expected table to be read. In the case of a too large ids count, this would often have been trapped by the existing sanity checks, but this patch introduces a more exact check, which can identify too small values. 2. It checks the contents of the index table for corruption. Link: https://lkml.kernel.org/r/20210204130249.4495-3-phillip@squashfs.org.uk Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Reported-by: syzbot+b06d57ba83f604522af2@syzkaller.appspotmail.com Reported-by: syzbot+c021ba012da41ee9807c@syzkaller.appspotmail.com Reported-by: syzbot+5024636e8b5fd19f0f19@syzkaller.appspotmail.com Reported-by: syzbot+bcbc661df46657d0fa4f@syzkaller.appspotmail.com Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
41 lines
1.1 KiB
C
41 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Squashfs - a compressed read only filesystem for Linux
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*
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* Copyright (c) 2010
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* Phillip Lougher <phillip@squashfs.org.uk>
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*
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* xattr.h
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*/
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#ifdef CONFIG_SQUASHFS_XATTR
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extern __le64 *squashfs_read_xattr_id_table(struct super_block *, u64,
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u64 *, int *);
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extern int squashfs_xattr_lookup(struct super_block *, unsigned int, int *,
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unsigned int *, unsigned long long *);
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#else
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static inline __le64 *squashfs_read_xattr_id_table(struct super_block *sb,
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u64 start, u64 *xattr_table_start, int *xattr_ids)
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{
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struct squashfs_xattr_id_table *id_table;
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id_table = squashfs_read_table(sb, start, sizeof(*id_table));
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if (IS_ERR(id_table))
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return (__le64 *) id_table;
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*xattr_table_start = le64_to_cpu(id_table->xattr_table_start);
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kfree(id_table);
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ERROR("Xattrs in filesystem, these will be ignored\n");
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return ERR_PTR(-ENOTSUPP);
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}
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static inline int squashfs_xattr_lookup(struct super_block *sb,
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unsigned int index, int *count, unsigned int *size,
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unsigned long long *xattr)
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{
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return 0;
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}
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#define squashfs_listxattr NULL
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#define squashfs_xattr_handlers NULL
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#endif
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