On Thu, Jul 06, 2017 at 08:55:43PM -0700, Darrick J. Wong wrote:
> 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.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
> libxfs/xfs_format.h | 1 +
> libxfs/xfs_symlink_remote.c | 2 +-
> libxfs/xfs_trans_resv.c | 4 ++--
> repair/dinode.c | 6 +++---
> repair/xfs_repair.c | 2 +-
> 5 files changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/libxfs/xfs_format.h b/libxfs/xfs_format.h
> index a53f035..79a72bb 100644
> --- a/libxfs/xfs_format.h
> +++ b/libxfs/xfs_format.h
> @@ -1211,6 +1211,7 @@ struct xfs_dsymlink_hdr {
>
> #define XFS_SYMLINK_CRC_OFF offsetof(struct xfs_dsymlink_hdr, sl_crc)
>
> +#define XFS_SYMLINK_MAXLEN 1024
> /*
> * The maximum pathlen is 1024 bytes. Since the minimum file system
> * blocksize is 512 bytes, we can get a max of 3 extents back from
> diff --git a/libxfs/xfs_symlink_remote.c b/libxfs/xfs_symlink_remote.c
> index 04c7446..d638530 100644
> --- a/libxfs/xfs_symlink_remote.c
> +++ b/libxfs/xfs_symlink_remote.c
> @@ -110,7 +110,7 @@ xfs_symlink_verify(
> if (bp->b_bn != be64_to_cpu(dsl->sl_blkno))
> return false;
> if (be32_to_cpu(dsl->sl_offset) +
> - be32_to_cpu(dsl->sl_bytes) >= MAXPATHLEN)
> + be32_to_cpu(dsl->sl_bytes) >= XFS_SYMLINK_MAXLEN)
> return false;
> if (dsl->sl_owner == 0)
> return false;
> diff --git a/libxfs/xfs_trans_resv.c b/libxfs/xfs_trans_resv.c
> index 5152a5b..d35a45f 100644
> --- a/libxfs/xfs_trans_resv.c
> +++ b/libxfs/xfs_trans_resv.c
> @@ -476,14 +476,14 @@ xfs_calc_mkdir_reservation(
> /*
> * Making a new symplink is the same as creating a new file, but
> * with the added blocks for remote symlink data which can be up to 1kB in
> - * length (MAXPATHLEN).
> + * length (XFS_SYMLINK_MAXLEN).
> */
> STATIC uint
> xfs_calc_symlink_reservation(
> struct xfs_mount *mp)
> {
> return xfs_calc_create_reservation(mp) +
> - xfs_calc_buf_res(1, MAXPATHLEN);
> + xfs_calc_buf_res(1, XFS_SYMLINK_MAXLEN);
> }
>
> /*
> 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);
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
