From 141a04400cd06f592cb07d819f90322e47565f0c Mon Sep 17 00:00:00 2001 From: brooks Date: Mon, 18 Feb 2019 18:57:52 +0000 Subject: [PATCH] MFC r344023: mdmfs: Fix many bugs in automatic md(4) creation. This code allocated a correctly sized buffer, read past the end of the source buffer, writing off the end of the target buffer, and then writing a '\0' terminator past the end of the target buffer (in the wrong place). It then leaked the buffer. Switch to a statically sized buffer on the stack and update the source pointer and length before use so the correct things are copied. Fix a logic error in the checks that the format of the line is as expected and move on out of an assert. Remove an unneeded close(). fclose() closes the descriptor. Found with: CheriABI Obtained from: CheriBSD Reviewed by: kib, jhb, markj Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D19122 --- sbin/mdmfs/mdmfs.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/sbin/mdmfs/mdmfs.c b/sbin/mdmfs/mdmfs.c index cbe64d4b537..55d1851ba5b 100644 --- a/sbin/mdmfs/mdmfs.c +++ b/sbin/mdmfs/mdmfs.c @@ -441,7 +441,8 @@ static void do_mdconfig_attach_au(const char *args, const enum md_types mdtype) { const char *ta; /* Type arg. */ - char *linep, *linebuf; /* Line pointer, line buffer. */ + char *linep; + char linebuf[12]; /* 32-bit unit (10) + '\n' (1) + '\0' (1) */ int fd; /* Standard output of mdconfig invocation. */ FILE *sfd; int rv; @@ -475,14 +476,15 @@ do_mdconfig_attach_au(const char *args, const enum md_types mdtype) if (sfd == NULL) err(1, "fdopen"); linep = fgetln(sfd, &linelen); - if (linep == NULL && linelen < mdnamelen + 1) - errx(1, "unexpected output from mdconfig (attach)"); /* If the output format changes, we want to know about it. */ - assert(strncmp(linep, mdname, mdnamelen) == 0); - linebuf = malloc(linelen - mdnamelen + 1); - assert(linebuf != NULL); + if (linep == NULL || linelen <= mdnamelen + 1 || + linelen - mdnamelen >= sizeof(linebuf) || + strncmp(linep, mdname, mdnamelen) != 0) + errx(1, "unexpected output from mdconfig (attach)"); + linep += mdnamelen; + linelen -= mdnamelen; /* Can't use strlcpy because linep is not NULL-terminated. */ - strncpy(linebuf, linep + mdnamelen, linelen); + strncpy(linebuf, linep, linelen); linebuf[linelen] = '\0'; ul = strtoul(linebuf, &p, 10); if (ul == ULONG_MAX || *p != '\n') @@ -490,7 +492,6 @@ do_mdconfig_attach_au(const char *args, const enum md_types mdtype) unit = ul; fclose(sfd); - close(fd); } /* -- 2.45.0