udf: Verify partition map count
[ Upstream commit 1a11201668e8635602577dcf06f2e96c591d8819 ] Verify that number of partition maps isn't insanely high which can lead to large allocation in udf_sb_alloc_partition_maps(). All partition maps have to fit in the LVD which is in a single block. Reported-by: syzbot+478f2c1a6f0f447a46bb@syzkaller.appspotmail.com Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Sasha Levin <sashal@kernel.org> [uli: backport to 4.19] Reviewed-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.x90@mail.toshiba> Reviewed-by: Pavel Machek <pavel@denx.de> Signed-off-by: Ulrich Hecht <uli@kernel.org>
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@@ -1414,7 +1414,7 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block,
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struct genericPartitionMap *gpm;
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uint16_t ident;
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struct buffer_head *bh;
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unsigned int table_len;
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unsigned int table_len, part_map_count;
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int ret;
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bh = udf_read_tagged(sb, block, block, &ident);
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@@ -1431,7 +1431,15 @@ static int udf_load_logicalvol(struct super_block *sb, sector_t block,
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goto out_bh;
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}
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ret = udf_sb_alloc_partition_maps(sb, le32_to_cpu(lvd->numPartitionMaps));
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part_map_count = le32_to_cpu(lvd->numPartitionMaps);
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if (part_map_count > table_len / sizeof(struct genericPartitionMap1)) {
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udf_err(sb, "error loading logical volume descriptor: "
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"Too many partition maps (%u > %u)\n", part_map_count,
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table_len / (unsigned)sizeof(struct genericPartitionMap1));
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ret = -EIO;
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goto out_bh;
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}
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ret = udf_sb_alloc_partition_maps(sb, part_map_count);
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if (ret)
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goto out_bh;
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