From: Jan Kara Date: Tue, 10 May 2022 10:36:04 +0000 (+0200) Subject: udf: Avoid using stale lengthOfImpUse X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=c1ad35dd0548ce947d97aaf92f7f2f9a202951cf;p=linux.git udf: Avoid using stale lengthOfImpUse udf_write_fi() uses lengthOfImpUse of the entry it is writing to. However this field has not yet been initialized so it either contains completely bogus value or value from last directory entry at that place. In either case this is wrong and can lead to filesystem corruption or kernel crashes. Reported-by: butt3rflyh4ck CC: stable@vger.kernel.org Fixes: 979a6e28dd96 ("udf: Get rid of 0-length arrays in struct fileIdentDesc") Signed-off-by: Jan Kara --- diff --git a/fs/udf/namei.c b/fs/udf/namei.c index 0ed4861b038f6..b3d5f97f16cdb 100644 --- a/fs/udf/namei.c +++ b/fs/udf/namei.c @@ -75,11 +75,11 @@ int udf_write_fi(struct inode *inode, struct fileIdentDesc *cfi, if (fileident) { if (adinicb || (offset + lfi < 0)) { - memcpy(udf_get_fi_ident(sfi), fileident, lfi); + memcpy(sfi->impUse + liu, fileident, lfi); } else if (offset >= 0) { memcpy(fibh->ebh->b_data + offset, fileident, lfi); } else { - memcpy(udf_get_fi_ident(sfi), fileident, -offset); + memcpy(sfi->impUse + liu, fileident, -offset); memcpy(fibh->ebh->b_data, fileident - offset, lfi + offset); } @@ -88,11 +88,11 @@ int udf_write_fi(struct inode *inode, struct fileIdentDesc *cfi, offset += lfi; if (adinicb || (offset + padlen < 0)) { - memset(udf_get_fi_ident(sfi) + lfi, 0x00, padlen); + memset(sfi->impUse + liu + lfi, 0x00, padlen); } else if (offset >= 0) { memset(fibh->ebh->b_data + offset, 0x00, padlen); } else { - memset(udf_get_fi_ident(sfi) + lfi, 0x00, -offset); + memset(sfi->impUse + liu + lfi, 0x00, -offset); memset(fibh->ebh->b_data, 0x00, padlen + offset); }