Make .{list,get}xattr routines adapted to long xattr name prefixes.
When the bit 7 of erofs_xattr_entry.e_name_index is set, it indicates
that it refers to a long xattr name prefix.
Signed-off-by: Jingbo Xu <jeffl...@linux.alibaba.com>
---
v3: introduce infix_len to struct getxattr_iter, and refactor the
implementation of xattr_entrymatch(), erofs_xattr_long_entrymatch(), and
xattr_namematch() accordingly.
The erofs_xattr_long_entrymatch() of v2 version will advance
it->name.name pointer by pf->infix_len prematurely, as the following
xattr_namematch() may fail (-ENOATTR) since mismatching. And then
it->name.name will be compared with the next xattr entry, while
it->name.name has been mistakenly modified in the previous round. This
will cause -ENOATTR error on the existing xattr.
---
fs/erofs/xattr.c | 68 +++++++++++++++++++++++++++++++++++++++---------
1 file changed, 56 insertions(+), 12 deletions(-)
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 684571e83a2c..a04724c816e5 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -297,17 +297,45 @@ struct getxattr_iter {
struct xattr_iter it;
char *buffer;
- int buffer_size, index;
+ int buffer_size, index, infix_len;
struct qstr name;
};
+static int erofs_xattr_long_entrymatch(struct getxattr_iter *it,
+ struct erofs_xattr_entry *entry)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(it->it.sb);
+ struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +
+ (entry->e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);
+
+ if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)
+ return -ENOATTR;
+
+ if (it->index != pf->prefix->base_index ||
+ it->name.len != entry->e_name_len + pf->infix_len)
+ return -ENOATTR;
+
+ if (memcmp(it->name.name, pf->prefix->infix, pf->infix_len))
+ return -ENOATTR;
+
+ it->infix_len = pf->infix_len;
+ return 0;
+}
+
static int xattr_entrymatch(struct xattr_iter *_it,
struct erofs_xattr_entry *entry)
{
struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
- return (it->index != entry->e_name_index ||
- it->name.len != entry->e_name_len) ? -ENOATTR : 0;
+ /* should also match the infix for long name prefixes */
+ if (entry->e_name_index & EROFS_XATTR_LONG_PREFIX)
+ return erofs_xattr_long_entrymatch(it, entry);
+
+ if (it->index != entry->e_name_index ||
+ it->name.len != entry->e_name_len)
+ return -ENOATTR;
+ it->infix_len = 0;
+ return 0;
}
static int xattr_namematch(struct xattr_iter *_it,
@@ -315,7 +343,9 @@ static int xattr_namematch(struct xattr_iter *_it,
{
struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
- return memcmp(buf, it->name.name + processed, len) ? -ENOATTR : 0;
+ if (memcmp(buf, it->name.name + it->infix_len + processed, len))
+ return -ENOATTR;
+ return 0;
}
static int xattr_checkbuffer(struct xattr_iter *_it,
@@ -487,12 +517,24 @@ static int xattr_entrylist(struct xattr_iter *_it,
{
struct listxattr_iter *it =
container_of(_it, struct listxattr_iter, it);
- unsigned int prefix_len;
- const char *prefix;
-
- const struct xattr_handler *h =
- erofs_xattr_handler(entry->e_name_index);
+ unsigned int base_index = entry->e_name_index;
+ unsigned int prefix_len, infix_len = 0;
+ const char *prefix, *infix = NULL;
+ const struct xattr_handler *h;
+
+ if (entry->e_name_index & EROFS_XATTR_LONG_PREFIX) {
+ struct erofs_sb_info *sbi = EROFS_SB(_it->sb);
+ struct erofs_xattr_prefix_item *pf = sbi->xattr_prefixes +
+ (entry->e_name_index & EROFS_XATTR_LONG_PREFIX_MASK);
+
+ if (pf >= sbi->xattr_prefixes + sbi->xattr_prefix_count)
+ return 1;
+ infix = pf->prefix->infix;
+ infix_len = pf->infix_len;
+ base_index = pf->prefix->base_index;
+ }
+ h = erofs_xattr_handler(base_index);
if (!h || (h->list && !h->list(it->dentry)))
return 1;
@@ -500,16 +542,18 @@ static int xattr_entrylist(struct xattr_iter *_it,
prefix_len = strlen(prefix);
if (!it->buffer) {
- it->buffer_ofs += prefix_len + entry->e_name_len + 1;
+ it->buffer_ofs += prefix_len + infix_len +
+ entry->e_name_len + 1;
return 1;
}
- if (it->buffer_ofs + prefix_len
+ if (it->buffer_ofs + prefix_len + infix_len +
+ entry->e_name_len + 1 > it->buffer_size)
return -ERANGE;
memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);
- it->buffer_ofs += prefix_len;
+ memcpy(it->buffer + it->buffer_ofs + prefix_len, infix, infix_len);
+ it->buffer_ofs += prefix_len + infix_len;
return 0;
}
--
2.19.1.6.gb485710b
