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9p: fix misuse of sscanf() in v9fs_stat2inode() 

1) sscanf() return value needs to be checked, damnit
2) sscanf() is perfectly capable of checking for fixed prefix,
no need for that %13s + strncmp with constant string.
3) st->extension is a valid string; no need for voodoo with
str*cpy() there.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2021-01-31 14:40:40 -05:00
parent b1adbdbda4
commit 9652c73246
1 changed files with 9 additions and 12 deletions
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21
fs/9p/vfs_inode.c
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@ -1137,9 +1137,6 @@ v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
struct super_block *sb, unsigned int flags) struct super_block *sb, unsigned int flags)
{ {
umode_t mode; umode_t mode;
char ext[32];
char tag_name[14];
unsigned int i_nlink;
struct v9fs_session_info *v9ses = sb->s_fs_info; struct v9fs_session_info *v9ses = sb->s_fs_info;
struct v9fs_inode *v9inode = V9FS_I(inode); struct v9fs_inode *v9inode = V9FS_I(inode);
@ -1157,18 +1154,18 @@ v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
inode->i_gid = stat->n_gid; inode->i_gid = stat->n_gid;
} }
if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) { if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
if (v9fs_proto_dotu(v9ses) && (stat->extension[0] != '\0')) { if (v9fs_proto_dotu(v9ses)) {
unsigned int i_nlink;
/* /*
* Hadlink support got added later to * Hadlink support got added later to the .u extension.
* to the .u extension. So there can be * So there can be a server out there that doesn't
* server out there that doesn't support * support this even with .u extension. That would
* this even with .u extension. So check * just leave us with stat->extension being an empty
* for non NULL stat->extension * string, though.
*/ */
strlcpy(ext, stat->extension, sizeof(ext));
/* HARDLINKCOUNT %u */ /* HARDLINKCOUNT %u */
sscanf(ext, "%13s %u", tag_name, &i_nlink); if (sscanf(stat->extension,
if (!strncmp(tag_name, "HARDLINKCOUNT", 13)) " HARDLINKCOUNT %u", &i_nlink) == 1)
set_nlink(inode, i_nlink); set_nlink(inode, i_nlink);
} }
} }