From bf29e886b242cebf6a96ca0e43873abc777e0b50 Mon Sep 17 00:00:00 2001 From: Hin-Tak Leung Date: Fri, 6 Jun 2014 14:36:22 -0700 Subject: [PATCH] hfsplus: correct usage of HFSPLUS_ATTR_MAX_STRLEN for non-English attributes HFSPLUS_ATTR_MAX_STRLEN (=127) is the limit of attribute names for the number of unicode character (UTF-16BE) storable in the HFS+ file system. Almost all the current usage of it is wrong, in relation to NLS to on-disk conversion. Except for one use calling hfsplus_asc2uni (which should stay the same) and its uses in calling hfsplus_uni2asc (which was corrected in the earlier patch in this series concerning usage of hfsplus_uni2asc), all the other uses are of the forms: - char buffer[size] - bound check: "if (namespace_adjusted_input_length > size) return failure;" Conversion between on-disk unicode representation and NLS char strings (in whichever direction) always needs to accommodate the worst-case NLS conversion, so all char buffers of that size need to have a NLS_MAX_CHARSET_SIZE x . The bound checks are all wrong, since they compare nls_length derived from strlen() to a unicode length limit. It turns out that all the bound-checks do is to protect hfsplus_asc2uni(), which can fail if the input is too large. There is only one usage of it as far as attributes are concerned, in hfsplus_attr_build_key(). It is in turn used by hfsplus_find_attr(), hfsplus_create_attr(), hfsplus_delete_attr(). Thus making sure that errors from hfsplus_asc2uni() is caught in hfsplus_attr_build_key() and propagated is sufficient to replace all the bound checks. Unpropagated errors from hfsplus_asc2uni() in the file catalog code was addressed recently in an independent patch "hfsplus: fix longname handling" by Sougata Santra. Before this patch, trying to set a 55 CJK character (in a UTF-8 locale, > 127/3=42) attribute plus user prefix fails with: $ setfattr -n user.`cat testing-string` -v `cat testing-string` \ testing-string setfattr: testing-string: Operation not supported and retrieving a stored long attributes is particular ugly(!): find /mnt/* -type f -exec getfattr -d {} \; getfattr: /mnt/testing-string: Input/output error with console log: [268008.389781] hfsplus: unicode conversion failed After the patch, both of the above works. FYI, the test attribute string is prepared with: echo -e -n \ "\xe9\x80\x99\xe6\x98\xaf\xe4\xb8\x80\xe5\x80\x8b\xe9\x9d\x9e\xe5" \ "\xb8\xb8\xe6\xbc\xab\xe9\x95\xb7\xe8\x80\x8c\xe6\xa5\xb5\xe5\x85" \ "\xb6\xe4\xb9\x8f\xe5\x91\xb3\xe5\x92\x8c\xe7\x9b\xb8\xe7\x95\xb6" \ "\xe7\x84\xa1\xe8\xb6\xa3\xe3\x80\x81\xe4\xbb\xa5\xe5\x8f\x8a\xe7" \ "\x84\xa1\xe7\x94\xa8\xe7\x9a\x84\xe3\x80\x81\xe5\x86\x8d\xe5\x8a" \ "\xa0\xe4\xb8\x8a\xe6\xaf\xab\xe7\x84\xa1\xe6\x84\x8f\xe7\xbe\xa9" \ "\xe7\x9a\x84\xe6\x93\xb4\xe5\xb1\x95\xe5\xb1\xac\xe6\x80\xa7\xef" \ "\xbc\x8c\xe8\x80\x8c\xe5\x85\xb6\xe5\x94\xaf\xe4\xb8\x80\xe5\x89" \ "\xb5\xe5\xbb\xba\xe7\x9b\xae\xe7\x9a\x84\xe5\x83\x85\xe6\x98\xaf" \ "\xe7\x82\xba\xe4\xba\x86\xe6\xb8\xac\xe8\xa9\xa6\xe4\xbd\x9c\xe7" \ "\x94\xa8\xe3\x80\x82" | tr -d ' ' (= "pointlessly long attribute for testing", elaborate Chinese in UTF-8 enoding). However, it is not possible to set double the size (110 + 5 is still under 127) in a UTF-8 locale: $setfattr -n user.`cat testing-string testing-string` -v \ `cat testing-string testing-string` testing-string setfattr: testing-string: Numerical result out of range 110 CJK char in UTF-8 is 330 bytes - the generic get/set attribute system call code in linux/fs/xattr.c imposes a 255 byte limit. One can use a combination of iconv to encode content, changing terminal locale for viewing, and an nls=cp932/cp936/cp949/cp950 mount option to fully use 127-unicode attribute in a double-byte locale. Also, as an additional information, it is possible to (mis-)use unicode half-width/full-width forms (U+FFxx) to write attributes which looks like english but not actually ascii. Thanks Anton Altaparmakov for reviewing the earlier ideas behind this change. [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: fix build] Signed-off-by: Hin-Tak Leung Cc: Anton Altaparmakov Cc: Vyacheslav Dubeyko Cc: Al Viro Cc: Christoph Hellwig Cc: Sougata Santra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/hfsplus/attributes.c | 11 +++------ fs/hfsplus/xattr.c | 36 ++++++++++++++++----------- fs/hfsplus/xattr_security.c | 49 +++++++++++++++++++++---------------- fs/hfsplus/xattr_trusted.c | 32 +++++++++++++++--------- fs/hfsplus/xattr_user.c | 32 +++++++++++++++--------- 5 files changed, 94 insertions(+), 66 deletions(-) diff --git a/fs/hfsplus/attributes.c b/fs/hfsplus/attributes.c index caf89a7be0a1..f3345c0b1c62 100644 --- a/fs/hfsplus/attributes.c +++ b/fs/hfsplus/attributes.c @@ -54,14 +54,11 @@ int hfsplus_attr_build_key(struct super_block *sb, hfsplus_btree_key *key, memset(key, 0, sizeof(struct hfsplus_attr_key)); key->attr.cnid = cpu_to_be32(cnid); if (name) { - len = strlen(name); - if (len > HFSPLUS_ATTR_MAX_STRLEN) { - pr_err("invalid xattr name's length\n"); - return -EINVAL; - } - hfsplus_asc2uni(sb, + int res = hfsplus_asc2uni(sb, (struct hfsplus_unistr *)&key->attr.key_name, - HFSPLUS_ATTR_MAX_STRLEN, name, len); + HFSPLUS_ATTR_MAX_STRLEN, name, strlen(name)); + if (res) + return res; len = be16_to_cpu(key->attr.key_name.length); } else { key->attr.key_name.length = 0; diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c index e2b3c9ea1c71..c03c94611cce 100644 --- a/fs/hfsplus/xattr.c +++ b/fs/hfsplus/xattr.c @@ -806,47 +806,55 @@ end_removexattr: static int hfsplus_osx_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size, int type) { - char xattr_name[HFSPLUS_ATTR_MAX_STRLEN + - XATTR_MAC_OSX_PREFIX_LEN + 1] = {0}; - size_t len = strlen(name); + char *xattr_name; + int res; if (!strcmp(name, "")) return -EINVAL; - if (len > HFSPLUS_ATTR_MAX_STRLEN) - return -EOPNOTSUPP; - /* * Don't allow retrieving properly prefixed attributes * by prepending them with "osx." */ if (is_known_namespace(name)) return -EOPNOTSUPP; + xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + + XATTR_MAC_OSX_PREFIX_LEN + 1, GFP_KERNEL); + if (!xattr_name) + return -ENOMEM; + strcpy(xattr_name, XATTR_MAC_OSX_PREFIX); + strcpy(xattr_name + XATTR_MAC_OSX_PREFIX_LEN, name); - return hfsplus_getxattr(dentry, xattr_name, buffer, size); + res = hfsplus_getxattr(dentry, xattr_name, buffer, size); + kfree(xattr_name); + return res; } static int hfsplus_osx_setxattr(struct dentry *dentry, const char *name, const void *buffer, size_t size, int flags, int type) { - char xattr_name[HFSPLUS_ATTR_MAX_STRLEN + - XATTR_MAC_OSX_PREFIX_LEN + 1] = {0}; - size_t len = strlen(name); + char *xattr_name; + int res; if (!strcmp(name, "")) return -EINVAL; - if (len > HFSPLUS_ATTR_MAX_STRLEN) - return -EOPNOTSUPP; - /* * Don't allow setting properly prefixed attributes * by prepending them with "osx." */ if (is_known_namespace(name)) return -EOPNOTSUPP; + xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + + XATTR_MAC_OSX_PREFIX_LEN + 1, GFP_KERNEL); + if (!xattr_name) + return -ENOMEM; + strcpy(xattr_name, XATTR_MAC_OSX_PREFIX); + strcpy(xattr_name + XATTR_MAC_OSX_PREFIX_LEN, name); - return hfsplus_setxattr(dentry, xattr_name, buffer, size, flags); + res = hfsplus_setxattr(dentry, xattr_name, buffer, size, flags); + kfree(xattr_name); + return res; } static size_t hfsplus_osx_listxattr(struct dentry *dentry, char *list, diff --git a/fs/hfsplus/xattr_security.c b/fs/hfsplus/xattr_security.c index 00722765ea79..6ec5e107691f 100644 --- a/fs/hfsplus/xattr_security.c +++ b/fs/hfsplus/xattr_security.c @@ -7,6 +7,8 @@ */ #include +#include + #include "hfsplus_fs.h" #include "xattr.h" #include "acl.h" @@ -14,37 +16,43 @@ static int hfsplus_security_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size, int type) { - char xattr_name[HFSPLUS_ATTR_MAX_STRLEN + 1] = {0}; - size_t len = strlen(name); + char *xattr_name; + int res; if (!strcmp(name, "")) return -EINVAL; - if (len + XATTR_SECURITY_PREFIX_LEN > HFSPLUS_ATTR_MAX_STRLEN) - return -EOPNOTSUPP; - + xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1, + GFP_KERNEL); + if (!xattr_name) + return -ENOMEM; strcpy(xattr_name, XATTR_SECURITY_PREFIX); strcpy(xattr_name + XATTR_SECURITY_PREFIX_LEN, name); - return hfsplus_getxattr(dentry, xattr_name, buffer, size); + res = hfsplus_getxattr(dentry, xattr_name, buffer, size); + kfree(xattr_name); + return res; } static int hfsplus_security_setxattr(struct dentry *dentry, const char *name, const void *buffer, size_t size, int flags, int type) { - char xattr_name[HFSPLUS_ATTR_MAX_STRLEN + 1] = {0}; - size_t len = strlen(name); + char *xattr_name; + int res; if (!strcmp(name, "")) return -EINVAL; - if (len + XATTR_SECURITY_PREFIX_LEN > HFSPLUS_ATTR_MAX_STRLEN) - return -EOPNOTSUPP; - + xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1, + GFP_KERNEL); + if (!xattr_name) + return -ENOMEM; strcpy(xattr_name, XATTR_SECURITY_PREFIX); strcpy(xattr_name + XATTR_SECURITY_PREFIX_LEN, name); - return hfsplus_setxattr(dentry, xattr_name, buffer, size, flags); + res = hfsplus_setxattr(dentry, xattr_name, buffer, size, flags); + kfree(xattr_name); + return res; } static size_t hfsplus_security_listxattr(struct dentry *dentry, char *list, @@ -62,31 +70,30 @@ static int hfsplus_initxattrs(struct inode *inode, void *fs_info) { const struct xattr *xattr; - char xattr_name[HFSPLUS_ATTR_MAX_STRLEN + 1] = {0}; - size_t xattr_name_len; + char *xattr_name; int err = 0; + xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1, + GFP_KERNEL); + if (!xattr_name) + return -ENOMEM; for (xattr = xattr_array; xattr->name != NULL; xattr++) { - xattr_name_len = strlen(xattr->name); - if (xattr_name_len == 0) + if (!strcmp(xattr->name, "")) continue; - if (xattr_name_len + XATTR_SECURITY_PREFIX_LEN > - HFSPLUS_ATTR_MAX_STRLEN) - return -EOPNOTSUPP; - strcpy(xattr_name, XATTR_SECURITY_PREFIX); strcpy(xattr_name + XATTR_SECURITY_PREFIX_LEN, xattr->name); memset(xattr_name + - XATTR_SECURITY_PREFIX_LEN + xattr_name_len, 0, 1); + XATTR_SECURITY_PREFIX_LEN + strlen(xattr->name), 0, 1); err = __hfsplus_setxattr(inode, xattr_name, xattr->value, xattr->value_len, 0); if (err) break; } + kfree(xattr_name); return err; } diff --git a/fs/hfsplus/xattr_trusted.c b/fs/hfsplus/xattr_trusted.c index 426cee277542..3c5f27e4746a 100644 --- a/fs/hfsplus/xattr_trusted.c +++ b/fs/hfsplus/xattr_trusted.c @@ -6,43 +6,51 @@ * Handler for trusted extended attributes. */ +#include + #include "hfsplus_fs.h" #include "xattr.h" static int hfsplus_trusted_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size, int type) { - char xattr_name[HFSPLUS_ATTR_MAX_STRLEN + 1] = {0}; - size_t len = strlen(name); + char *xattr_name; + int res; if (!strcmp(name, "")) return -EINVAL; - if (len + XATTR_TRUSTED_PREFIX_LEN > HFSPLUS_ATTR_MAX_STRLEN) - return -EOPNOTSUPP; - + xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1, + GFP_KERNEL); + if (!xattr_name) + return -ENOMEM; strcpy(xattr_name, XATTR_TRUSTED_PREFIX); strcpy(xattr_name + XATTR_TRUSTED_PREFIX_LEN, name); - return hfsplus_getxattr(dentry, xattr_name, buffer, size); + res = hfsplus_getxattr(dentry, xattr_name, buffer, size); + kfree(xattr_name); + return res; } static int hfsplus_trusted_setxattr(struct dentry *dentry, const char *name, const void *buffer, size_t size, int flags, int type) { - char xattr_name[HFSPLUS_ATTR_MAX_STRLEN + 1] = {0}; - size_t len = strlen(name); + char *xattr_name; + int res; if (!strcmp(name, "")) return -EINVAL; - if (len + XATTR_TRUSTED_PREFIX_LEN > HFSPLUS_ATTR_MAX_STRLEN) - return -EOPNOTSUPP; - + xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1, + GFP_KERNEL); + if (!xattr_name) + return -ENOMEM; strcpy(xattr_name, XATTR_TRUSTED_PREFIX); strcpy(xattr_name + XATTR_TRUSTED_PREFIX_LEN, name); - return hfsplus_setxattr(dentry, xattr_name, buffer, size, flags); + res = hfsplus_setxattr(dentry, xattr_name, buffer, size, flags); + kfree(xattr_name); + return res; } static size_t hfsplus_trusted_listxattr(struct dentry *dentry, char *list, diff --git a/fs/hfsplus/xattr_user.c b/fs/hfsplus/xattr_user.c index e34016561ae0..2b625a538b64 100644 --- a/fs/hfsplus/xattr_user.c +++ b/fs/hfsplus/xattr_user.c @@ -6,43 +6,51 @@ * Handler for user extended attributes. */ +#include + #include "hfsplus_fs.h" #include "xattr.h" static int hfsplus_user_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size, int type) { - char xattr_name[HFSPLUS_ATTR_MAX_STRLEN + 1] = {0}; - size_t len = strlen(name); + char *xattr_name; + int res; if (!strcmp(name, "")) return -EINVAL; - if (len + XATTR_USER_PREFIX_LEN > HFSPLUS_ATTR_MAX_STRLEN) - return -EOPNOTSUPP; - + xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1, + GFP_KERNEL); + if (!xattr_name) + return -ENOMEM; strcpy(xattr_name, XATTR_USER_PREFIX); strcpy(xattr_name + XATTR_USER_PREFIX_LEN, name); - return hfsplus_getxattr(dentry, xattr_name, buffer, size); + res = hfsplus_getxattr(dentry, xattr_name, buffer, size); + kfree(xattr_name); + return res; } static int hfsplus_user_setxattr(struct dentry *dentry, const char *name, const void *buffer, size_t size, int flags, int type) { - char xattr_name[HFSPLUS_ATTR_MAX_STRLEN + 1] = {0}; - size_t len = strlen(name); + char *xattr_name; + int res; if (!strcmp(name, "")) return -EINVAL; - if (len + XATTR_USER_PREFIX_LEN > HFSPLUS_ATTR_MAX_STRLEN) - return -EOPNOTSUPP; - + xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1, + GFP_KERNEL); + if (!xattr_name) + return -ENOMEM; strcpy(xattr_name, XATTR_USER_PREFIX); strcpy(xattr_name + XATTR_USER_PREFIX_LEN, name); - return hfsplus_setxattr(dentry, xattr_name, buffer, size, flags); + res = hfsplus_setxattr(dentry, xattr_name, buffer, size, flags); + kfree(xattr_name); + return res; } static size_t hfsplus_user_listxattr(struct dentry *dentry, char *list, -- 2.20.1