Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754899AbbBQCFu (ORCPT ); Mon, 16 Feb 2015 21:05:50 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33882 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752106AbbBQBu7 (ORCPT ); Mon, 16 Feb 2015 20:50:59 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Jan Kara" , "Carl Henrik Lunde" Date: Tue, 17 Feb 2015 01:46:53 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 070/152] udf: Check path length when reading symlink In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7054 Lines: 233 3.2.67-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit 0e5cc9a40ada6046e6bc3bdfcd0c0d7e4b706b14 upstream. Symlink reading code does not check whether the resulting path fits into the page provided by the generic code. This isn't as easy as just checking the symlink size because of various encoding conversions we perform on path. So we have to check whether there is still enough space in the buffer on the fly. Reported-by: Carl Henrik Lunde Signed-off-by: Jan Kara [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- fs/udf/dir.c | 3 ++- fs/udf/namei.c | 3 ++- fs/udf/symlink.c | 31 ++++++++++++++++++++++++++----- fs/udf/udfdecl.h | 3 ++- fs/udf/unicode.c | 28 ++++++++++++++++------------ 5 files changed, 48 insertions(+), 20 deletions(-) --- a/fs/udf/dir.c +++ b/fs/udf/dir.c @@ -163,7 +163,8 @@ static int do_udf_readdir(struct inode * struct kernel_lb_addr tloc = lelb_to_cpu(cfi.icb.extLocation); iblock = udf_get_lb_pblock(dir->i_sb, &tloc, 0); - flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi); + flen = udf_get_filename(dir->i_sb, nameptr, lfi, fname, + UDF_NAME_LEN); dt_type = DT_UNKNOWN; } --- a/fs/udf/namei.c +++ b/fs/udf/namei.c @@ -235,7 +235,8 @@ static struct fileIdentDesc *udf_find_en if (!lfi) continue; - flen = udf_get_filename(dir->i_sb, nameptr, fname, lfi); + flen = udf_get_filename(dir->i_sb, nameptr, lfi, fname, + UDF_NAME_LEN); if (flen && udf_match(flen, fname, child->len, child->name)) goto out_ok; } --- a/fs/udf/symlink.c +++ b/fs/udf/symlink.c @@ -30,13 +30,16 @@ #include #include "udf_i.h" -static void udf_pc_to_char(struct super_block *sb, unsigned char *from, - int fromlen, unsigned char *to) +static int udf_pc_to_char(struct super_block *sb, unsigned char *from, + int fromlen, unsigned char *to, int tolen) { struct pathComponent *pc; int elen = 0; + int comp_len; unsigned char *p = to; + /* Reserve one byte for terminating \0 */ + tolen--; while (elen < fromlen) { pc = (struct pathComponent *)(from + elen); switch (pc->componentType) { @@ -49,22 +52,37 @@ static void udf_pc_to_char(struct super_ break; /* Fall through */ case 2: + if (tolen == 0) + return -ENAMETOOLONG; p = to; *p++ = '/'; + tolen--; break; case 3: + if (tolen < 3) + return -ENAMETOOLONG; memcpy(p, "../", 3); p += 3; + tolen -= 3; break; case 4: + if (tolen < 2) + return -ENAMETOOLONG; memcpy(p, "./", 2); p += 2; + tolen -= 2; /* that would be . - just ignore */ break; case 5: - p += udf_get_filename(sb, pc->componentIdent, p, - pc->lengthComponentIdent); + comp_len = udf_get_filename(sb, pc->componentIdent, + pc->lengthComponentIdent, + p, tolen); + p += comp_len; + tolen -= comp_len; + if (tolen == 0) + return -ENAMETOOLONG; *p++ = '/'; + tolen--; break; } elen += sizeof(struct pathComponent) + pc->lengthComponentIdent; @@ -73,6 +91,7 @@ static void udf_pc_to_char(struct super_ p[-1] = '\0'; else p[0] = '\0'; + return 0; } static int udf_symlink_filler(struct file *file, struct page *page) @@ -108,8 +127,10 @@ static int udf_symlink_filler(struct fil symlink = bh->b_data; } - udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p); + err = udf_pc_to_char(inode->i_sb, symlink, inode->i_size, p, PAGE_SIZE); brelse(bh); + if (err) + goto out_unlock_inode; up_read(&iinfo->i_data_sem); SetPageUptodate(page); --- a/fs/udf/udfdecl.h +++ b/fs/udf/udfdecl.h @@ -207,7 +207,8 @@ udf_get_lb_pblock(struct super_block *sb } /* unicode.c */ -extern int udf_get_filename(struct super_block *, uint8_t *, uint8_t *, int); +extern int udf_get_filename(struct super_block *, uint8_t *, int, uint8_t *, + int); extern int udf_put_filename(struct super_block *, const uint8_t *, uint8_t *, int); extern int udf_build_ustr(struct ustr *, dstring *, int); --- a/fs/udf/unicode.c +++ b/fs/udf/unicode.c @@ -28,7 +28,8 @@ #include "udf_sb.h" -static int udf_translate_to_linux(uint8_t *, uint8_t *, int, uint8_t *, int); +static int udf_translate_to_linux(uint8_t *, int, uint8_t *, int, uint8_t *, + int); static int udf_char_to_ustr(struct ustr *dest, const uint8_t *src, int strlen) { @@ -333,8 +334,8 @@ try_again: return u_len + 1; } -int udf_get_filename(struct super_block *sb, uint8_t *sname, uint8_t *dname, - int flen) +int udf_get_filename(struct super_block *sb, uint8_t *sname, int slen, + uint8_t *dname, int dlen) { struct ustr *filename, *unifilename; int len = 0; @@ -347,7 +348,7 @@ int udf_get_filename(struct super_block if (!unifilename) goto out1; - if (udf_build_ustr_exact(unifilename, sname, flen)) + if (udf_build_ustr_exact(unifilename, sname, slen)) goto out2; if (UDF_QUERY_FLAG(sb, UDF_FLAG_UTF8)) { @@ -366,7 +367,8 @@ int udf_get_filename(struct super_block } else goto out2; - len = udf_translate_to_linux(dname, filename->u_name, filename->u_len, + len = udf_translate_to_linux(dname, dlen, + filename->u_name, filename->u_len, unifilename->u_name, unifilename->u_len); out2: kfree(unifilename); @@ -403,10 +405,12 @@ int udf_put_filename(struct super_block #define EXT_MARK '.' #define CRC_MARK '#' #define EXT_SIZE 5 +/* Number of chars we need to store generated CRC to make filename unique */ +#define CRC_LEN 5 -static int udf_translate_to_linux(uint8_t *newName, uint8_t *udfName, - int udfLen, uint8_t *fidName, - int fidNameLen) +static int udf_translate_to_linux(uint8_t *newName, int newLen, + uint8_t *udfName, int udfLen, + uint8_t *fidName, int fidNameLen) { int index, newIndex = 0, needsCRC = 0; int extIndex = 0, newExtIndex = 0, hasExt = 0; @@ -440,7 +444,7 @@ static int udf_translate_to_linux(uint8_ newExtIndex = newIndex; } } - if (newIndex < 256) + if (newIndex < newLen) newName[newIndex++] = curr; else needsCRC = 1; @@ -468,13 +472,13 @@ static int udf_translate_to_linux(uint8_ } ext[localExtIndex++] = curr; } - maxFilenameLen = 250 - localExtIndex; + maxFilenameLen = newLen - CRC_LEN - localExtIndex; if (newIndex > maxFilenameLen) newIndex = maxFilenameLen; else newIndex = newExtIndex; - } else if (newIndex > 250) - newIndex = 250; + } else if (newIndex > newLen - CRC_LEN) + newIndex = newLen - CRC_LEN; newName[newIndex++] = CRC_MARK; valueCRC = crc_itu_t(0, fidName, fidNameLen); newName[newIndex++] = hexChar[(valueCRC & 0xf000) >> 12]; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/