Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933263AbbDIIxe (ORCPT ); Thu, 9 Apr 2015 04:53:34 -0400 Received: from mail.kernel.org ([198.145.29.136]:41849 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933240AbbDIIx1 (ORCPT ); Thu, 9 Apr 2015 04:53:27 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jan Kara , Zefan Li Subject: [PATCH 3.4 073/176] udf: Check path length when reading symlink Date: Thu, 9 Apr 2015 16:45:21 +0800 Message-Id: <1428569224-23820-73-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1428569028-23762-1-git-send-email-lizf@kernel.org> References: <1428569028-23762-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7800 Lines: 246 From: Jan Kara 3.4.107-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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 [lizf: Backported to 3.4: udf_get_filename() is called in do_udf_readdir()] Signed-off-by: Zefan Li --- 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(-) diff --git a/fs/udf/dir.c b/fs/udf/dir.c index eb8bfe2..56341af 100644 --- a/fs/udf/dir.c +++ b/fs/udf/dir.c @@ -163,7 +163,8 @@ static int do_udf_readdir(struct inode *dir, struct file *filp, 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; } diff --git a/fs/udf/namei.c b/fs/udf/namei.c index 78bff11..407c129 100644 --- a/fs/udf/namei.c +++ b/fs/udf/namei.c @@ -233,7 +233,8 @@ static struct fileIdentDesc *udf_find_entry(struct inode *dir, 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; } diff --git a/fs/udf/symlink.c b/fs/udf/symlink.c index d89f324..2d0c372 100644 --- 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_block *sb, unsigned char *from, 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_block *sb, unsigned char *from, 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 file *file, struct page *page) 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); diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h index ebe1031..375f648 100644 --- a/fs/udf/udfdecl.h +++ b/fs/udf/udfdecl.h @@ -207,7 +207,8 @@ udf_get_lb_pblock(struct super_block *sb, struct kernel_lb_addr *loc, } /* 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); diff --git a/fs/udf/unicode.c b/fs/udf/unicode.c index 44b815e..d29c06f 100644 --- 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 *sb, uint8_t *sname, uint8_t *dname, 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 *sb, uint8_t *sname, uint8_t *dname, } 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 *sb, const uint8_t *sname, #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_t *newName, uint8_t *udfName, 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_t *newName, uint8_t *udfName, } 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]; -- 1.9.1 -- 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/