On 7/31/17 4:07 PM, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> XFS has a maximum symlink target length of 1024 bytes; this is a
> holdover from the Irix days. Unfortunately, the constant establishing
> this was 'MAXPATHLEN', and is /not/ the same as the Linux MAXPATHLEN,
> which is 4096.
>
> The kernel enforces its 1024 byte MAXPATHLEN on symlink targets, but
> xfsprogs picks up the (Linux) system 4096 byte MAXPATHLEN, which means
> that xfs_repair doesn't complain about oversized symlinks.
>
> Since this is an on-disk format constraint, put the define in the XFS
> namespace. As a side effect of the rename, xfs_repair wil detect
> oversized symlinks and clean them off the system.
null_check() is only used for symlinks today, but it's not described
as such, so I was on the fence about shortening the ASSERT in there.
but meh, not worth haggling over.
Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> repair/dinode.c | 6 +++---
> repair/xfs_repair.c | 2 +-
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
>
> diff --git a/repair/dinode.c b/repair/dinode.c
> index da87217..f005335 100644
> --- a/repair/dinode.c
> +++ b/repair/dinode.c
> @@ -1259,7 +1259,7 @@ null_check(char *name, int length)
> {
> int i;
>
> - ASSERT(length < MAXPATHLEN);
> + ASSERT(length < XFS_SYMLINK_MAXLEN);
>
> for (i = 0; i < length; i++, name++) {
> if (*name == '\0')
> @@ -1371,7 +1371,7 @@ process_symlink(
> blkmap_t *blkmap)
> {
> char *symlink;
> - char data[MAXPATHLEN];
> + char data[XFS_SYMLINK_MAXLEN];
>
> /*
> * check size against kernel symlink limits. we know
> @@ -1379,7 +1379,7 @@ process_symlink(
> * the inode is structurally ok so we don't have to check
> * for that
> */
> - if (be64_to_cpu(dino->di_size) >= MAXPATHLEN) {
> + if (be64_to_cpu(dino->di_size) >= XFS_SYMLINK_MAXLEN) {
> do_warn(_("symlink in inode %" PRIu64 " too long (%llu chars)\n"),
> lino, (unsigned long long) be64_to_cpu(dino->di_size));
> return(1);
> diff --git a/repair/xfs_repair.c b/repair/xfs_repair.c
> index ab60c0f..b2dd91b 100644
> --- a/repair/xfs_repair.c
> +++ b/repair/xfs_repair.c
> @@ -761,7 +761,7 @@ main(int argc, char **argv)
> glob_agcount = mp->m_sb.sb_agcount;
>
> chunks_pblock = mp->m_sb.sb_inopblock / XFS_INODES_PER_CHUNK;
> - max_symlink_blocks = libxfs_symlink_blocks(mp, MAXPATHLEN);
> + max_symlink_blocks = libxfs_symlink_blocks(mp, XFS_SYMLINK_MAXLEN);
> inodes_per_cluster = MAX(mp->m_sb.sb_inopblock,
> mp->m_inode_cluster_size >> mp->m_sb.sb_inodelog);
>
>
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