| Message ID | 20240529082634.141286-5-eugen.hristev@collabora.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Case insensitive cleanup for ext4/f2fs | expand |
Eugen Hristev <eugen.hristev@collabora.com> writes: > From: Gabriel Krisman Bertazi <krisman@collabora.com> > > Instead of reimplementing ext4_match_ci, use the new libfs helper. > > It also adds a comment explaining why fname->cf_name.name must be > checked prior to the encryption hash optimization, because that tripped > me before. > > Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> > Signed-off-by: Eugen Hristev <eugen.hristev@collabora.com> > Reviewed-by: Eric Biggers <ebiggers@google.com> > --- > fs/ext4/namei.c | 91 +++++++++++++++---------------------------------- > 1 file changed, 27 insertions(+), 64 deletions(-) > > diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c > index ec4c9bfc1057..20668741a23c 100644 > --- a/fs/ext4/namei.c > +++ b/fs/ext4/namei.c > @@ -1390,58 +1390,6 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block) > } > > #if IS_ENABLED(CONFIG_UNICODE) > -/* > - * Test whether a case-insensitive directory entry matches the filename > - * being searched for. If quick is set, assume the name being looked up > - * is already in the casefolded form. > - * > - * Returns: 0 if the directory entry matches, more than 0 if it > - * doesn't match or less than zero on error. > - */ > -static int ext4_ci_compare(const struct inode *parent, const struct qstr *name, > - u8 *de_name, size_t de_name_len, bool quick) > -{ > - 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 entry = QSTR_INIT(de_name, de_name_len); > - int ret; > - > - if (IS_ENCRYPTED(parent)) { > - const struct fscrypt_str encrypted_name = > - FSTR_INIT(de_name, de_name_len); > - > - decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL); > - if (!decrypted_name.name) > - return -ENOMEM; > - ret = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name, > - &decrypted_name); > - if (ret < 0) > - goto out; > - entry.name = decrypted_name.name; > - entry.len = decrypted_name.len; > - } > - > - if (quick) > - ret = utf8_strncasecmp_folded(um, name, &entry); > - else > - ret = utf8_strncasecmp(um, name, &entry); > - if (ret < 0) { > - /* Handle invalid character sequence as either an error > - * or as an opaque byte sequence. > - */ > - if (sb_has_strict_encoding(sb)) > - ret = -EINVAL; > - else if (name->len != entry.len) > - ret = 1; > - else > - ret = !!memcmp(name->name, entry.name, entry.len); > - } > -out: > - kfree(decrypted_name.name); > - return ret; > -} > - > int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname, > struct ext4_filename *name) > { > @@ -1503,20 +1451,35 @@ static bool ext4_match(struct inode *parent, > #if IS_ENABLED(CONFIG_UNICODE) > if (IS_CASEFOLDED(parent) && > (!IS_ENCRYPTED(parent) || fscrypt_has_encryption_key(parent))) { > - if (fname->cf_name.name) { > - if (IS_ENCRYPTED(parent)) { > - if (fname->hinfo.hash != EXT4_DIRENT_HASH(de) || > - fname->hinfo.minor_hash != > - EXT4_DIRENT_MINOR_HASH(de)) { > + int ret; > > - return false; > - } > - } > - return !ext4_ci_compare(parent, &fname->cf_name, > - de->name, de->name_len, true); > + /* > + * Just checking IS_ENCRYPTED(parent) below is not > + * sufficient to decide whether one can use the hash for > + * skipping the string comparison, because the key might > + * have been added right after > + * ext4_fname_setup_ci_filename(). In this case, a hash > + * mismatch will be a false negative. Therefore, make > + * sure cf_name was properly initialized before > + * considering the calculated hash. > + */ > + if (IS_ENCRYPTED(parent) && fname->cf_name.name && > + (fname->hinfo.hash != EXT4_DIRENT_HASH(de) || > + fname->hinfo.minor_hash != EXT4_DIRENT_MINOR_HASH(de))) > + return false; > + > + ret = generic_ci_match(parent, fname->usr_fname, > + &fname->cf_name, de->name, > + de->name_len); > + if (ret < 0) { > + /* > + * Treat comparison errors as not a match. The > + * only case where it happens is on a disk > + * corruption or ENOMEM. > + */ > + return false; > } > - return !ext4_ci_compare(parent, fname->usr_fname, de->name, > - de->name_len, false); With the changes to patch 3 in this iteration, This could become: /* * Treat comparison errors as not a match. The * only case where it happens is disk corruption * or ENOMEM. */ return ext4_ci_compare(parent, fname->usr_fname, de->name, de->name_len, false) > 0;
On 6/4/24 22:17, Gabriel Krisman Bertazi wrote: > Eugen Hristev <eugen.hristev@collabora.com> writes: > >> From: Gabriel Krisman Bertazi <krisman@collabora.com> >> >> Instead of reimplementing ext4_match_ci, use the new libfs helper. >> >> It also adds a comment explaining why fname->cf_name.name must be >> checked prior to the encryption hash optimization, because that tripped >> me before. >> >> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> >> Signed-off-by: Eugen Hristev <eugen.hristev@collabora.com> >> Reviewed-by: Eric Biggers <ebiggers@google.com> >> --- >> fs/ext4/namei.c | 91 +++++++++++++++---------------------------------- >> 1 file changed, 27 insertions(+), 64 deletions(-) >> >> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c >> index ec4c9bfc1057..20668741a23c 100644 >> --- a/fs/ext4/namei.c >> +++ b/fs/ext4/namei.c >> @@ -1390,58 +1390,6 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block) >> } >> >> #if IS_ENABLED(CONFIG_UNICODE) >> -/* >> - * Test whether a case-insensitive directory entry matches the filename >> - * being searched for. If quick is set, assume the name being looked up >> - * is already in the casefolded form. >> - * >> - * Returns: 0 if the directory entry matches, more than 0 if it >> - * doesn't match or less than zero on error. >> - */ >> -static int ext4_ci_compare(const struct inode *parent, const struct qstr *name, >> - u8 *de_name, size_t de_name_len, bool quick) >> -{ >> - 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 entry = QSTR_INIT(de_name, de_name_len); >> - int ret; >> - >> - if (IS_ENCRYPTED(parent)) { >> - const struct fscrypt_str encrypted_name = >> - FSTR_INIT(de_name, de_name_len); >> - >> - decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL); >> - if (!decrypted_name.name) >> - return -ENOMEM; >> - ret = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name, >> - &decrypted_name); >> - if (ret < 0) >> - goto out; >> - entry.name = decrypted_name.name; >> - entry.len = decrypted_name.len; >> - } >> - >> - if (quick) >> - ret = utf8_strncasecmp_folded(um, name, &entry); >> - else >> - ret = utf8_strncasecmp(um, name, &entry); >> - if (ret < 0) { >> - /* Handle invalid character sequence as either an error >> - * or as an opaque byte sequence. >> - */ >> - if (sb_has_strict_encoding(sb)) >> - ret = -EINVAL; >> - else if (name->len != entry.len) >> - ret = 1; >> - else >> - ret = !!memcmp(name->name, entry.name, entry.len); >> - } >> -out: >> - kfree(decrypted_name.name); >> - return ret; >> -} >> - >> int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname, >> struct ext4_filename *name) >> { >> @@ -1503,20 +1451,35 @@ static bool ext4_match(struct inode *parent, >> #if IS_ENABLED(CONFIG_UNICODE) >> if (IS_CASEFOLDED(parent) && >> (!IS_ENCRYPTED(parent) || fscrypt_has_encryption_key(parent))) { >> - if (fname->cf_name.name) { >> - if (IS_ENCRYPTED(parent)) { >> - if (fname->hinfo.hash != EXT4_DIRENT_HASH(de) || >> - fname->hinfo.minor_hash != >> - EXT4_DIRENT_MINOR_HASH(de)) { >> + int ret; >> >> - return false; >> - } >> - } >> - return !ext4_ci_compare(parent, &fname->cf_name, >> - de->name, de->name_len, true); >> + /* >> + * Just checking IS_ENCRYPTED(parent) below is not >> + * sufficient to decide whether one can use the hash for >> + * skipping the string comparison, because the key might >> + * have been added right after >> + * ext4_fname_setup_ci_filename(). In this case, a hash >> + * mismatch will be a false negative. Therefore, make >> + * sure cf_name was properly initialized before >> + * considering the calculated hash. >> + */ >> + if (IS_ENCRYPTED(parent) && fname->cf_name.name && >> + (fname->hinfo.hash != EXT4_DIRENT_HASH(de) || >> + fname->hinfo.minor_hash != EXT4_DIRENT_MINOR_HASH(de))) >> + return false; >> + >> + ret = generic_ci_match(parent, fname->usr_fname, >> + &fname->cf_name, de->name, >> + de->name_len); >> + if (ret < 0) { >> + /* >> + * Treat comparison errors as not a match. The >> + * only case where it happens is on a disk >> + * corruption or ENOMEM. >> + */ >> + return false; >> } >> - return !ext4_ci_compare(parent, fname->usr_fname, de->name, >> - de->name_len, false); > > With the changes to patch 3 in this iteration, This could become: > > /* > * Treat comparison errors as not a match. The > * only case where it happens is disk corruption > * or ENOMEM. > */ > return ext4_ci_compare(parent, fname->usr_fname, de->name, > de->name_len, false) > 0; > Do you mean return generic_ci_match(parent, fname->usr_fname, &fname->cf_name, de->name, de->name_len) > 0; ? Because ext4_ci_compare was obsoleted with this series. Thanks, Eugen
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index ec4c9bfc1057..20668741a23c 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -1390,58 +1390,6 @@ static void dx_insert_block(struct dx_frame *frame, u32 hash, ext4_lblk_t block) } #if IS_ENABLED(CONFIG_UNICODE) -/* - * Test whether a case-insensitive directory entry matches the filename - * being searched for. If quick is set, assume the name being looked up - * is already in the casefolded form. - * - * Returns: 0 if the directory entry matches, more than 0 if it - * doesn't match or less than zero on error. - */ -static int ext4_ci_compare(const struct inode *parent, const struct qstr *name, - u8 *de_name, size_t de_name_len, bool quick) -{ - 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 entry = QSTR_INIT(de_name, de_name_len); - int ret; - - if (IS_ENCRYPTED(parent)) { - const struct fscrypt_str encrypted_name = - FSTR_INIT(de_name, de_name_len); - - decrypted_name.name = kmalloc(de_name_len, GFP_KERNEL); - if (!decrypted_name.name) - return -ENOMEM; - ret = fscrypt_fname_disk_to_usr(parent, 0, 0, &encrypted_name, - &decrypted_name); - if (ret < 0) - goto out; - entry.name = decrypted_name.name; - entry.len = decrypted_name.len; - } - - if (quick) - ret = utf8_strncasecmp_folded(um, name, &entry); - else - ret = utf8_strncasecmp(um, name, &entry); - if (ret < 0) { - /* Handle invalid character sequence as either an error - * or as an opaque byte sequence. - */ - if (sb_has_strict_encoding(sb)) - ret = -EINVAL; - else if (name->len != entry.len) - ret = 1; - else - ret = !!memcmp(name->name, entry.name, entry.len); - } -out: - kfree(decrypted_name.name); - return ret; -} - int ext4_fname_setup_ci_filename(struct inode *dir, const struct qstr *iname, struct ext4_filename *name) { @@ -1503,20 +1451,35 @@ static bool ext4_match(struct inode *parent, #if IS_ENABLED(CONFIG_UNICODE) if (IS_CASEFOLDED(parent) && (!IS_ENCRYPTED(parent) || fscrypt_has_encryption_key(parent))) { - if (fname->cf_name.name) { - if (IS_ENCRYPTED(parent)) { - if (fname->hinfo.hash != EXT4_DIRENT_HASH(de) || - fname->hinfo.minor_hash != - EXT4_DIRENT_MINOR_HASH(de)) { + int ret; - return false; - } - } - return !ext4_ci_compare(parent, &fname->cf_name, - de->name, de->name_len, true); + /* + * Just checking IS_ENCRYPTED(parent) below is not + * sufficient to decide whether one can use the hash for + * skipping the string comparison, because the key might + * have been added right after + * ext4_fname_setup_ci_filename(). In this case, a hash + * mismatch will be a false negative. Therefore, make + * sure cf_name was properly initialized before + * considering the calculated hash. + */ + if (IS_ENCRYPTED(parent) && fname->cf_name.name && + (fname->hinfo.hash != EXT4_DIRENT_HASH(de) || + fname->hinfo.minor_hash != EXT4_DIRENT_MINOR_HASH(de))) + return false; + + ret = generic_ci_match(parent, fname->usr_fname, + &fname->cf_name, de->name, + de->name_len); + if (ret < 0) { + /* + * Treat comparison errors as not a match. The + * only case where it happens is on a disk + * corruption or ENOMEM. + */ + return false; } - return !ext4_ci_compare(parent, fname->usr_fname, de->name, - de->name_len, false); + return ret; } #endif