On 4/9/12 11:34 PM, Eric Sandeen wrote:
> xfs_metadump currently obfuscates entire symlinks without regard
> to path components; this can lead to a corrupt image when restoring
> a metadump containing extremely long symlinks:
>
> Phase 3 - for each AG...
> - scan and clear agi unlinked lists...
> - process known inodes and perform inode discovery...
> - agno = 0
> component of symlink in inode 145 too long
> problem with symbolic link in inode 145
> cleared inode 145
> ... <more trail of woe>
>
> Fix this by consolidating symlink obfuscation into a new
> function which obfuscates one path component at a time.
>
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
ping? :)
> ---
>
> Yes, I need to do an xfstest for this. metadumping a filesystem
> after fsstressing it works well.
>
> diff --git a/db/metadump.c b/db/metadump.c
> index c5ffddb..9f15d9e 100644
> --- a/db/metadump.c
> +++ b/db/metadump.c
> @@ -956,6 +956,40 @@ obfuscate_sf_dir(
> }
>
> static void
> +obfuscate_path_components(
> + char *buf,
> + __uint64_t len)
> +{
> + uchar_t *comp;
> + xfs_dahash_t hash;
> +
> + comp = (uchar_t *)buf;
> + while (comp < (uchar_t *)buf + len) {
> + char *slash;
> + int namelen;
> +
> + /* find slash at end of this component */
> + slash = strchr((char *)comp, '/');
> + if (!slash) {
> + /* last (or single) component */
> + namelen = strlen((char *)comp);
> + hash = libxfs_da_hashname(comp, namelen);
> + obfuscate_name(hash, namelen, comp);
> + break;
> + }
> + namelen = slash - (char *)comp;
> + /* handle leading or consecutive slashes */
> + if (!namelen) {
> + comp++;
> + continue;
> + }
> + hash = libxfs_da_hashname(comp, namelen);
> + obfuscate_name(hash, namelen, comp);
> + comp += namelen + 1;
> + }
> +}
> +
> +static void
> obfuscate_sf_symlink(
> xfs_dinode_t *dip)
> {
> @@ -971,8 +1005,7 @@ obfuscate_sf_symlink(
> }
>
> buf = (char *)XFS_DFORK_DPTR(dip);
> - while (len > 0)
> - buf[--len] = random() % 127 + 1;
> + obfuscate_path_components(buf, len);
> }
>
> static void
> @@ -1176,11 +1209,8 @@ obfuscate_symlink_blocks(
> char *block,
> xfs_dfilblks_t count)
> {
> - int i;
> -
> count <<= mp->m_sb.sb_blocklog;
> - for (i = 0; i < count; i++)
> - block[i] = random() % 127 + 1;
> + obfuscate_path_components(block, count);
> }
>
> #define MAX_REMOTE_VALS 4095
>
> _______________________________________________
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> xfs@xxxxxxxxxxx
> http://oss.sgi.com/mailman/listinfo/xfs
>
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