diff options
| -rw-r--r-- | fs/xfs/libxfs/xfs_da_format.h | 75 | ||||
| -rw-r--r-- | fs/xfs/libxfs/xfs_fs.h | 4 | ||||
| -rw-r--r-- | fs/xfs/xfs_ondisk.h | 5 |
3 files changed, 71 insertions, 13 deletions
diff --git a/fs/xfs/libxfs/xfs_da_format.h b/fs/xfs/libxfs/xfs_da_format.h index 25e2841084e1..f9015f88eca7 100644 --- a/fs/xfs/libxfs/xfs_da_format.h +++ b/fs/xfs/libxfs/xfs_da_format.h @@ -591,7 +591,7 @@ struct xfs_attr_shortform { uint8_t valuelen; /* actual length of value (no NULL) */ uint8_t flags; /* flags bits (see xfs_attr_leaf.h) */ uint8_t nameval[]; /* name & value bytes concatenated */ - } list[1]; /* variable sized array */ + } list[]; /* variable sized array */ }; typedef struct xfs_attr_leaf_map { /* RLE map of free bytes */ @@ -620,19 +620,29 @@ typedef struct xfs_attr_leaf_entry { /* sorted on key, not name */ typedef struct xfs_attr_leaf_name_local { __be16 valuelen; /* number of bytes in value */ __u8 namelen; /* length of name bytes */ - __u8 nameval[1]; /* name/value bytes */ + /* + * In Linux 6.5 this flex array was converted from nameval[1] to + * nameval[]. Be very careful here about extra padding at the end; + * see xfs_attr_leaf_entsize_local() for details. + */ + __u8 nameval[]; /* name/value bytes */ } xfs_attr_leaf_name_local_t; typedef struct xfs_attr_leaf_name_remote { __be32 valueblk; /* block number of value bytes */ __be32 valuelen; /* number of bytes in value */ __u8 namelen; /* length of name bytes */ - __u8 name[1]; /* name bytes */ + /* + * In Linux 6.5 this flex array was converted from name[1] to name[]. + * Be very careful here about extra padding at the end; see + * xfs_attr_leaf_entsize_remote() for details. + */ + __u8 name[]; /* name bytes */ } xfs_attr_leaf_name_remote_t; typedef struct xfs_attr_leafblock { xfs_attr_leaf_hdr_t hdr; /* constant-structure header block */ - xfs_attr_leaf_entry_t entries[1]; /* sorted on key, not name */ + xfs_attr_leaf_entry_t entries[]; /* sorted on key, not name */ /* * The rest of the block contains the following structures after the * leaf entries, growing from the bottom up. The variables are never @@ -664,7 +674,7 @@ struct xfs_attr3_leaf_hdr { struct xfs_attr3_leafblock { struct xfs_attr3_leaf_hdr hdr; - struct xfs_attr_leaf_entry entries[1]; + struct xfs_attr_leaf_entry entries[]; /* * The rest of the block contains the following structures after the @@ -747,14 +757,61 @@ xfs_attr3_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx) */ static inline int xfs_attr_leaf_entsize_remote(int nlen) { - return round_up(sizeof(struct xfs_attr_leaf_name_remote) - 1 + - nlen, XFS_ATTR_LEAF_NAME_ALIGN); + /* + * Prior to Linux 6.5, struct xfs_attr_leaf_name_remote ended with + * name[1], which was used as a flexarray. The layout of this struct + * is 9 bytes of fixed-length fields followed by a __u8 flex array at + * offset 9. + * + * On most architectures, struct xfs_attr_leaf_name_remote had two + * bytes of implicit padding at the end of the struct to make the + * struct length 12. After converting name[1] to name[], there are + * three implicit padding bytes and the struct size remains 12. + * However, there are compiler configurations that do not add implicit + * padding at all (m68k) and have been broken for years. + * + * This entsize computation historically added (the xattr name length) + * to (the padded struct length - 1) and rounded that sum up to the + * nearest multiple of 4 (NAME_ALIGN). IOWs, round_up(11 + nlen, 4). + * This is encoded in the ondisk format, so we cannot change this. + * + * Compute the entsize from offsetof of the flexarray and manually + * adding bytes for the implicit padding. + */ + const size_t remotesize = + offsetof(struct xfs_attr_leaf_name_remote, name) + 2; + + return round_up(remotesize + nlen, XFS_ATTR_LEAF_NAME_ALIGN); } static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen) { - return round_up(sizeof(struct xfs_attr_leaf_name_local) - 1 + - nlen + vlen, XFS_ATTR_LEAF_NAME_ALIGN); + /* + * Prior to Linux 6.5, struct xfs_attr_leaf_name_local ended with + * nameval[1], which was used as a flexarray. The layout of this + * struct is 3 bytes of fixed-length fields followed by a __u8 flex + * array at offset 3. + * + * struct xfs_attr_leaf_name_local had zero bytes of implicit padding + * at the end of the struct to make the struct length 4. On most + * architectures, after converting nameval[1] to nameval[], there is + * one implicit padding byte and the struct size remains 4. However, + * there are compiler configurations that do not add implicit padding + * at all (m68k) and would break. + * + * This entsize computation historically added (the xattr name and + * value length) to (the padded struct length - 1) and rounded that sum + * up to the nearest multiple of 4 (NAME_ALIGN). IOWs, the formula is + * round_up(3 + nlen + vlen, 4). This is encoded in the ondisk format, + * so we cannot change this. + * + * Compute the entsize from offsetof of the flexarray and manually + * adding bytes for the implicit padding. + */ + const size_t localsize = + offsetof(struct xfs_attr_leaf_name_local, nameval); + + return round_up(localsize + nlen + vlen, XFS_ATTR_LEAF_NAME_ALIGN); } static inline int xfs_attr_leaf_entsize_local_max(int bsize) diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h index 9c60ebb328b4..2cbf9ea39b8c 100644 --- a/fs/xfs/libxfs/xfs_fs.h +++ b/fs/xfs/libxfs/xfs_fs.h @@ -592,12 +592,12 @@ typedef struct xfs_attrlist_cursor { struct xfs_attrlist { __s32 al_count; /* number of entries in attrlist */ __s32 al_more; /* T/F: more attrs (do call again) */ - __s32 al_offset[1]; /* byte offsets of attrs [var-sized] */ + __s32 al_offset[]; /* byte offsets of attrs [var-sized] */ }; struct xfs_attrlist_ent { /* data from attr_list() */ __u32 a_valuelen; /* number bytes in value of attr */ - char a_name[1]; /* attr name (NULL terminated) */ + char a_name[]; /* attr name (NULL terminated) */ }; typedef struct xfs_fsop_attrlist_handlereq { diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h index 9737b5a9f405..c4cc99b70dd3 100644 --- a/fs/xfs/xfs_ondisk.h +++ b/fs/xfs/xfs_ondisk.h @@ -56,7 +56,7 @@ xfs_check_ondisk_structs(void) /* dir/attr trees */ XFS_CHECK_STRUCT_SIZE(struct xfs_attr3_leaf_hdr, 80); - XFS_CHECK_STRUCT_SIZE(struct xfs_attr3_leafblock, 88); + XFS_CHECK_STRUCT_SIZE(struct xfs_attr3_leafblock, 80); XFS_CHECK_STRUCT_SIZE(struct xfs_attr3_rmt_hdr, 56); XFS_CHECK_STRUCT_SIZE(struct xfs_da3_blkinfo, 56); XFS_CHECK_STRUCT_SIZE(struct xfs_da3_intnode, 64); @@ -88,7 +88,8 @@ xfs_check_ondisk_structs(void) XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, valuelen, 4); XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, namelen, 8); XFS_CHECK_OFFSET(xfs_attr_leaf_name_remote_t, name, 9); - XFS_CHECK_STRUCT_SIZE(xfs_attr_leafblock_t, 40); + XFS_CHECK_STRUCT_SIZE(xfs_attr_leafblock_t, 32); + XFS_CHECK_STRUCT_SIZE(struct xfs_attr_shortform, 4); XFS_CHECK_OFFSET(struct xfs_attr_shortform, hdr.totsize, 0); XFS_CHECK_OFFSET(struct xfs_attr_shortform, hdr.count, 2); XFS_CHECK_OFFSET(struct xfs_attr_shortform, list[0].namelen, 4); |