From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=5.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FROM,MAILING_LIST_MULTI, RCVD_IN_MSPIKE_H2 autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 27566 invoked from network); 29 Mar 2023 08:38:32 -0000 Received: from second.openwall.net (193.110.157.125) by inbox.vuxu.org with ESMTPUTF8; 29 Mar 2023 08:38:32 -0000 Received: (qmail 10116 invoked by uid 550); 29 Mar 2023 08:38:28 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: musl@lists.openwall.com Received: (qmail 10081 invoked from network); 29 Mar 2023 08:38:27 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1680079095; h=to:subject:message-id:date:from:mime-version:from:to:cc:subject :date:message-id:reply-to; bh=t6bIZdWb8wwtQ60/2uU3xIiLhV9tOr7yJm9+cb4gVJQ=; b=VsujdUG+r23B6r50cv9vwRaO8Rx6dJxT9NFAosK7bgRcJPi0ijl9BWO74iskpgmciX 722kFGAkxeWHCI6tsEgTb1RIBibx1tNySHEwUf3oP8KcoBTR/c330Y2sTufdIwdOUTzO GHXOW1ninHtakVr4nbfMVvKtXLvbtS1RfhJ7BwiWm0B2K05TSZJjzGhazvXC/9r5eIjt /+Zc4yZ9bGhyAWfEtiUSMq1fFsHpofAduqAmu3HnvE44/WwG4G2tk3NGX4CnuwciZxRd AEjezQRDRqtILagYppLLS+R3SMhFgfB/PZKrPl9SiSDJjyDnXyut/Yps9ugD8/Gnp1L/ fMJw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680079095; h=to:subject:message-id:date:from:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=t6bIZdWb8wwtQ60/2uU3xIiLhV9tOr7yJm9+cb4gVJQ=; b=8G8PIKE9oi6uIfIlQMs6fIno3h2ywIJMsHlYyYEwalt4LK81/yN02v6UVbBxtSdhRW joR5xOrJgt1CdKOpCESJ6xVEvuySlDb1+KwcMXucoH400R/2vMUVR/DrdyW6lTzasWgm XKS6ov/bwodkOqJ2czqP3lI5dSqg0LUpYpSeHPOG5EyWCmixBmcdxnrr0At6slMdOrBB PU4CrJAdMiOUlm6Uja0spXqqxYu/qdpAXfoBAxa7Fh22sPeraVtt9TOP0FofcrEs30Zy 8LNkWHz+OqIkov2JtF88YkLCs+53XLyW1BmQT/vhQTmZLpZiyVz30hCVrDQh4kRGtLbp L5QQ== X-Gm-Message-State: AAQBX9dUVwORi/YzIdxDrLATtGe5r22vX5IVpYHd+KwNMvX6YyLO+w+n TYm3no0D260AXXlV2L1qDUOvWvNpv2kMb9Xti3IOGWFGI34hZA== X-Google-Smtp-Source: AKy350amp6uwoBT3SkY8vCKvpaUonClmeAJ0bRMZtYXoz26ay0JTbKCnbUvEwpyDjNCTED6ySPbMIctuwWj6C0uNuHM= X-Received: by 2002:a05:6130:c14:b0:68a:8f33:9567 with SMTP id cg20-20020a0561300c1400b0068a8f339567mr12531234uab.2.1680079095351; Wed, 29 Mar 2023 01:38:15 -0700 (PDT) MIME-Version: 1.0 From: =?UTF-8?Q?Matthias_G=C3=B6rgens?= Date: Wed, 29 Mar 2023 16:38:04 +0800 Message-ID: To: musl@lists.openwall.com Content-Type: text/plain; charset="UTF-8" Subject: [musl] [PATCH] mntent: deal with escaped whitespace in mtab and fstab >From ca1001f856e314b0ea9d0f3a5d7c88106f151c2e Mon Sep 17 00:00:00 2001 From: Matthias Goergens Date: Wed, 29 Mar 2023 16:17:49 +0800 Subject: [PATCH] mntent: deal with escaped whitespace in mtab and fstab >From glibc's documentation: > Since fields in the mtab and fstab files are separated by whitespace, > octal escapes are used to represent the characters space (\040), > tab (\011), newline (\012), and backslash (\\) in those files when they > occur in one of the four strings in a mntent structure. The > routines addmntent() and getmntent() will convert from string > representation to escaped representation and back. When converting > from escaped representation, the sequence \134 is also converted to a > backslash. This fixes the issue reported in https://www.openwall.com/lists/musl/2021/12/14/1 This is my first time contributing to musl. Please point out any mistakes you can find. I am not quite sure I understand everything, and have also probably gotten the style wrong? Thanks! --- src/misc/mntent.c | 71 ++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 64 insertions(+), 7 deletions(-) diff --git a/src/misc/mntent.c b/src/misc/mntent.c index d404fbe3..527acc01 100644 --- a/src/misc/mntent.c +++ b/src/misc/mntent.c @@ -20,6 +20,34 @@ int endmntent(FILE *f) return 1; } +static inline int decode1(char** in_buf, char** out_buf, const char* from, const char to) { + if(strncmp(from, *in_buf, strlen(from)) == 0) { + *(*out_buf)++ = to; + *in_buf += strlen(from); + return 1; + } + return 0; +} + +static inline char* decode(char* buf) { + char* read_cursor = buf; + char* write_cursor = buf; + while(read_cursor && *read_cursor) { + // space + decode1(&read_cursor, &write_cursor, "\\040", '\040') + // tab + || decode1(&read_cursor, &write_cursor, "\\011", '\011') + // newline + || decode1(&read_cursor, &write_cursor, "\\012", '\012') + // backslash + || decode1(&read_cursor, &write_cursor, "\\134", '\134') + || decode1(&read_cursor, &write_cursor, "\\\\", '\\') + // default: copy char as is. + || (*write_cursor++ = *read_cursor++); + } + return buf; +} + struct mntent *getmntent_r(FILE *f, struct mntent *mnt, char *linebuf, int buflen) { int n[8], use_internal = (linebuf == SENTINEL); @@ -55,10 +83,10 @@ struct mntent *getmntent_r(FILE *f, struct mntent *mnt, char *linebuf, int bufle linebuf[n[5]] = 0; linebuf[n[7]] = 0; - mnt->mnt_fsname = linebuf+n[0]; - mnt->mnt_dir = linebuf+n[2]; - mnt->mnt_type = linebuf+n[4]; - mnt->mnt_opts = linebuf+n[6]; + mnt->mnt_fsname = decode(linebuf+n[0]); + mnt->mnt_dir = decode(linebuf+n[2]); + mnt->mnt_type = decode(linebuf+n[4]); + mnt->mnt_opts = decode(linebuf+n[6]); return mnt; } @@ -69,12 +97,41 @@ struct mntent *getmntent(FILE *f) return getmntent_r(f, &mnt, SENTINEL, 0); } +static inline int write_string(FILE *f, const char* str) +{ + char c; + int error_occured = 0; + while(str && !error_occured && (c = *str++) != 0) { + if(c == '\040') // space + error_occured = fprintf(f, "%s", "\\040") < 0; + else if (c == '\011') // tab + error_occured = fprintf(f, "%s", "\\011") < 0; + else if (c == '\012') // newline + error_occured = fprintf(f, "%s", "\\012") < 0; + else if (c == '\\') + error_occured = fprintf(f, "%s", "\\\\") < 0; + else + error_occured = fprintf(f, "%c", c) < 0; + } + return error_occured; +} + int addmntent(FILE *f, const struct mntent *mnt) { if (fseek(f, 0, SEEK_END)) return 1; - return fprintf(f, "%s\t%s\t%s\t%s\t%d\t%d\n", - mnt->mnt_fsname, mnt->mnt_dir, mnt->mnt_type, mnt->mnt_opts, - mnt->mnt_freq, mnt->mnt_passno) < 0; + flockfile(f); + int result = + write_string(f, mnt->mnt_fsname) + || (fprintf(f, "\t") < 0) + || write_string(f, mnt->mnt_dir) + || (fprintf(f, "\t") < 0) + || write_string(f, mnt->mnt_type) + || (fprintf(f, "\t") < 0) + || write_string(f, mnt->mnt_opts) + || (fprintf(f, "\t%d\t%d\n", + mnt->mnt_freq, mnt->mnt_passno) < 0); + funlockfile(f); + return result; } char *hasmntopt(const struct mntent *mnt, const char *opt) -- 2.40.0