| Message ID | 20240529082634.141286-4-eugen.hristev@collabora.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Case insensitive cleanup for ext4/f2fs | expand |
On Wed, May 29, 2024 at 11:26:30AM +0300, Eugen Hristev via Linux-f2fs-devel wrote: > + /* > + * Attempt a case-sensitive match first. It is cheaper and > + * should cover most lookups, including all the sane > + * applications that expect a case-sensitive filesystem. > + */ > + > + if (dirent.len == (folded_name->name ? folded_name->len : name->len) && > + !memcmp(name->name, dirent.name, dirent.len)) > + goto out; Shouldn't it be just 'name->len' instead of '(folded_name->name ? folded_name->len : name->len)'? - Eric
On 5/31/24 07:48, Eric Biggers wrote: > On Wed, May 29, 2024 at 11:26:30AM +0300, Eugen Hristev via Linux-f2fs-devel wrote: >> + /* >> + * Attempt a case-sensitive match first. It is cheaper and >> + * should cover most lookups, including all the sane >> + * applications that expect a case-sensitive filesystem. >> + */ >> + >> + if (dirent.len == (folded_name->name ? folded_name->len : name->len) && >> + !memcmp(name->name, dirent.name, dirent.len)) >> + goto out; > > Shouldn't it be just 'name->len' instead of > '(folded_name->name ? folded_name->len : name->len)'? Okay, I will change it. I am also waiting for other reviews to prepare the next version. Thanks for looking at this. Eugen > > - Eric > _______________________________________________ > Kernel mailing list -- kernel@mailman.collabora.com > To unsubscribe send an email to kernel-leave@mailman.collabora.com > This list is managed by https://mailman.collabora.com
Eugen Hristev <eugen.hristev@collabora.com> writes: > From: Gabriel Krisman Bertazi <krisman@collabora.com> > > generic_ci_match can be used by case-insensitive filesystems to compare > strings under lookup with dirents in a case-insensitive way. This > function is currently reimplemented by each filesystem supporting > casefolding, so this reduces code duplication in filesystem-specific > code. > > Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> > [eugen.hristev@collabora.com: rework to first test the exact match, cleanup > and add error message] > Signed-off-by: Eugen Hristev <eugen.hristev@collabora.com> Other than the origin of the length in memcmp mentioned by Eric, this patch looks good to me now. Thanks again for picking up this work! > --- > fs/libfs.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/fs.h | 4 +++ > 2 files changed, 78 insertions(+) > > diff --git a/fs/libfs.c b/fs/libfs.c > index b635ee5adbcc..6a6cfa2d7d93 100644 > --- a/fs/libfs.c > +++ b/fs/libfs.c > @@ -1854,6 +1854,80 @@ static const struct dentry_operations generic_ci_dentry_ops = { > .d_revalidate = fscrypt_d_revalidate, > #endif > }; > + > +/** > + * generic_ci_match() - Match a name (case-insensitively) with a dirent. > + * This is a filesystem helper for comparison with directory entries. > + * generic_ci_d_compare should be used in VFS' ->d_compare instead. > + * > + * @parent: Inode of the parent of the dirent under comparison > + * @name: name under lookup. > + * @folded_name: Optional pre-folded name under lookup > + * @de_name: Dirent name. > + * @de_name_len: dirent name length. > + * > + * Test whether a case-insensitive directory entry matches the filename > + * being searched. If @folded_name is provided, it is used instead of > + * recalculating the casefold of @name. > + * > + * Return: > 0 if the directory entry matches, 0 if it doesn't match, or > + * < 0 on error. > + */ > +int generic_ci_match(const struct inode *parent, > + const struct qstr *name, > + const struct qstr *folded_name, > + const u8 *de_name, u32 de_name_len) > +{ > + const struct super_block *sb = parent->i_sb; > + const struct unicode_map *um = sb->s_encoding; > + struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len); > + struct qstr dirent = QSTR_INIT(de_name, de_name_len); > + int res = 0; > + > + if (IS_ENCRYPTED(parent)) { > + const struct fscrypt_str encrypted_name = > + FSTR_INIT((u8 *) de_name, de_name_len); > + > + if (WARN_ON_ONCE(!fscrypt_has_encryption_key(parent))) > + return -EINVAL; > + > + decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL); > + if (!decrypted_name.name) > + return -ENOMEM; > + res = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name, > + &decrypted_name); > + if (res < 0) { > + kfree(decrypted_name.name); > + return res; > + } > + dirent.name = decrypted_name.name; > + dirent.len = decrypted_name.len; > + } > + > + /* > + * Attempt a case-sensitive match first. It is cheaper and > + * should cover most lookups, including all the sane > + * applications that expect a case-sensitive filesystem. > + */ > + > + if (dirent.len == (folded_name->name ? folded_name->len : name->len) && > + !memcmp(name->name, dirent.name, dirent.len)) > + goto out; > + > + if (folded_name->name) > + res = utf8_strncasecmp_folded(um, folded_name, &dirent); > + else > + res = utf8_strncasecmp(um, name, &dirent); > + > +out: > + kfree(decrypted_name.name); > + if (res < 0 && sb_has_strict_encoding(sb)) { > + pr_err_ratelimited("Directory contains filename that is invalid UTF-8"); > + return 0; > + } > + return !res; > +} > +EXPORT_SYMBOL(generic_ci_match); > #endif > > #ifdef CONFIG_FS_ENCRYPTION > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 639885621608..f8ca264a0edc 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -3367,6 +3367,10 @@ extern int generic_file_fsync(struct file *, loff_t, loff_t, int); > extern int generic_check_addressable(unsigned, u64); > > extern void generic_set_sb_d_ops(struct super_block *sb); > +extern int generic_ci_match(const struct inode *parent, > + const struct qstr *name, > + const struct qstr *folded_name, > + const u8 *de_name, u32 de_name_len); > > static inline bool sb_has_encoding(const struct super_block *sb) > {
diff --git a/fs/libfs.c b/fs/libfs.c index b635ee5adbcc..6a6cfa2d7d93 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1854,6 +1854,80 @@ static const struct dentry_operations generic_ci_dentry_ops = { .d_revalidate = fscrypt_d_revalidate, #endif }; + +/** + * generic_ci_match() - Match a name (case-insensitively) with a dirent. + * This is a filesystem helper for comparison with directory entries. + * generic_ci_d_compare should be used in VFS' ->d_compare instead. + * + * @parent: Inode of the parent of the dirent under comparison + * @name: name under lookup. + * @folded_name: Optional pre-folded name under lookup + * @de_name: Dirent name. + * @de_name_len: dirent name length. + * + * Test whether a case-insensitive directory entry matches the filename + * being searched. If @folded_name is provided, it is used instead of + * recalculating the casefold of @name. + * + * Return: > 0 if the directory entry matches, 0 if it doesn't match, or + * < 0 on error. + */ +int generic_ci_match(const struct inode *parent, + const struct qstr *name, + const struct qstr *folded_name, + const u8 *de_name, u32 de_name_len) +{ + const struct super_block *sb = parent->i_sb; + const struct unicode_map *um = sb->s_encoding; + struct fscrypt_str decrypted_name = FSTR_INIT(NULL, de_name_len); + struct qstr dirent = QSTR_INIT(de_name, de_name_len); + int res = 0; + + if (IS_ENCRYPTED(parent)) { + const struct fscrypt_str encrypted_name = + FSTR_INIT((u8 *) de_name, de_name_len); + + if (WARN_ON_ONCE(!fscrypt_has_encryption_key(parent))) + return -EINVAL; + + decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL); + if (!decrypted_name.name) + return -ENOMEM; + res = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name, + &decrypted_name); + if (res < 0) { + kfree(decrypted_name.name); + return res; + } + dirent.name = decrypted_name.name; + dirent.len = decrypted_name.len; + } + + /* + * Attempt a case-sensitive match first. It is cheaper and + * should cover most lookups, including all the sane + * applications that expect a case-sensitive filesystem. + */ + + if (dirent.len == (folded_name->name ? folded_name->len : name->len) && + !memcmp(name->name, dirent.name, dirent.len)) + goto out; + + if (folded_name->name) + res = utf8_strncasecmp_folded(um, folded_name, &dirent); + else + res = utf8_strncasecmp(um, name, &dirent); + +out: + kfree(decrypted_name.name); + if (res < 0 && sb_has_strict_encoding(sb)) { + pr_err_ratelimited("Directory contains filename that is invalid UTF-8"); + return 0; + } + return !res; +} +EXPORT_SYMBOL(generic_ci_match); #endif #ifdef CONFIG_FS_ENCRYPTION diff --git a/include/linux/fs.h b/include/linux/fs.h index 639885621608..f8ca264a0edc 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3367,6 +3367,10 @@ extern int generic_file_fsync(struct file *, loff_t, loff_t, int); extern int generic_check_addressable(unsigned, u64); extern void generic_set_sb_d_ops(struct super_block *sb); +extern int generic_ci_match(const struct inode *parent, + const struct qstr *name, + const struct qstr *folded_name, + const u8 *de_name, u32 de_name_len); static inline bool sb_has_encoding(const struct super_block *sb) {