From 6674ecab9004dcc4d8a65744f581b9ccf1f17504 Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 9 Dec 2019 11:10:57 +0000 Subject: fs/adfs: bigdir: extract directory validation Extract the directory validation from the directory reading function as we will want to re-use this code. Signed-off-by: Russell King Signed-off-by: Al Viro --- fs/adfs/dir_fplus.c | 41 +++++++++++++++++++++++++++++++---------- 1 file changed, 31 insertions(+), 10 deletions(-) diff --git a/fs/adfs/dir_fplus.c b/fs/adfs/dir_fplus.c index 393921f5121e..b83a74e9ff6d 100644 --- a/fs/adfs/dir_fplus.c +++ b/fs/adfs/dir_fplus.c @@ -16,6 +16,30 @@ static unsigned int adfs_fplus_offset(const struct adfs_bigdirheader *h, pos * sizeof(struct adfs_bigdirentry); } +static int adfs_fplus_validate_header(const struct adfs_bigdirheader *h) +{ + unsigned int size = le32_to_cpu(h->bigdirsize); + + if (h->bigdirversion[0] != 0 || h->bigdirversion[1] != 0 || + h->bigdirversion[2] != 0 || + h->bigdirstartname != cpu_to_le32(BIGDIRSTARTNAME) || + size & 2047) + return -EIO; + + return 0; +} + +static int adfs_fplus_validate_tail(const struct adfs_bigdirheader *h, + const struct adfs_bigdirtail *t) +{ + if (t->bigdirendname != cpu_to_le32(BIGDIRENDNAME) || + t->bigdirendmasseq != h->startmasseq || + t->reserved[0] != 0 || t->reserved[1] != 0) + return -EIO; + + return 0; +} + static int adfs_fplus_read(struct super_block *sb, u32 indaddr, unsigned int size, struct adfs_dir *dir) { @@ -30,6 +54,11 @@ static int adfs_fplus_read(struct super_block *sb, u32 indaddr, return ret; dir->bighead = h = (void *)dir->bhs[0]->b_data; + if (adfs_fplus_validate_header(h)) { + adfs_error(sb, "dir %06x has malformed header", indaddr); + goto out; + } + dirsize = le32_to_cpu(h->bigdirsize); if (dirsize != size) { adfs_msg(sb, KERN_WARNING, @@ -37,13 +66,6 @@ static int adfs_fplus_read(struct super_block *sb, u32 indaddr, indaddr, dirsize, size); } - if (h->bigdirversion[0] != 0 || h->bigdirversion[1] != 0 || - h->bigdirversion[2] != 0 || size & 2047 || - h->bigdirstartname != cpu_to_le32(BIGDIRSTARTNAME)) { - adfs_error(sb, "dir %06x has malformed header", indaddr); - goto out; - } - /* Read remaining buffers */ ret = adfs_dir_read_buffers(sb, indaddr, dirsize, dir); if (ret) @@ -52,9 +74,8 @@ static int adfs_fplus_read(struct super_block *sb, u32 indaddr, dir->bigtail = t = (struct adfs_bigdirtail *) (dir->bhs[dir->nr_buffers - 1]->b_data + (sb->s_blocksize - 8)); - if (t->bigdirendname != cpu_to_le32(BIGDIRENDNAME) || - t->bigdirendmasseq != h->startmasseq || - t->reserved[0] != 0 || t->reserved[1] != 0) { + ret = adfs_fplus_validate_tail(h, t); + if (ret) { adfs_error(sb, "dir %06x has malformed tail", indaddr); goto out; } -- cgit