Date: Wed, 13 Dec 2023 20:06:35 GMT From: Dag-Erling =?utf-8?Q?Sm=C3=B8rgrav?= <des@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 817f2d83bd50 - stable/13 - tail: Fix heap overflow in -F case. Message-ID: <202312132006.3BDK6Z2M087665@gitrepo.freebsd.org>
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The branch stable/13 has been updated by des: URL: https://cgit.FreeBSD.org/src/commit/?id=817f2d83bd50e88cb85e38e551fdaa5e79116b17 commit 817f2d83bd50e88cb85e38e551fdaa5e79116b17 Author: Dag-Erling Smørgrav <des@FreeBSD.org> AuthorDate: 2023-11-29 21:48:50 +0000 Commit: Dag-Erling Smørgrav <des@FreeBSD.org> CommitDate: 2023-12-13 16:39:38 +0000 tail: Fix heap overflow in -F case. The number of events we track can vary over time, but we only allocate enough space for the exact number of events we are tracking when we first begin, resulting in a trivially reproducable heap overflow. Fix this by allocating enough space for the greatest possible number of events (two per file) and clean up the code a bit. Also add a test case which triggers the aforementioned heap overflow, although we don't currently have a way to detect it. MFC after: 1 week Sponsored by: Klara, Inc. Reviewed by: allanjude, markj Differential Revision: https://reviews.freebsd.org/D42839 (cherry picked from commit 621f45532c5887c96b708ce232c52878d0053325) tail: Clean up error messages. MFC after: 1 week Sponsored by: Klara, Inc. Reviewed by: markj Differential Revision: https://reviews.freebsd.org/D42842 (cherry picked from commit b70e57be2cfe83ec9f410e2f317ea38aaac61a98) --- usr.bin/tail/forward.c | 39 ++++++++++++++++++--------------------- usr.bin/tail/read.c | 8 ++++---- usr.bin/tail/reverse.c | 2 +- usr.bin/tail/tail.c | 6 +++--- usr.bin/tail/tests/tail_test.sh | 21 ++++++++++++++++++++- 5 files changed, 46 insertions(+), 30 deletions(-) diff --git a/usr.bin/tail/forward.c b/usr.bin/tail/forward.c index e2a3eb77aade..a0f66262608a 100644 --- a/usr.bin/tail/forward.c +++ b/usr.bin/tail/forward.c @@ -275,7 +275,7 @@ set_events(file_info_t *files) action = USE_KQUEUE; for (i = 0, file = files; i < no_files; i++, file++) { - if (! file->fp) + if (!file->fp) continue; if (fstatfs(fileno(file->fp), &sf) == 0 && @@ -307,27 +307,21 @@ set_events(file_info_t *files) void follow(file_info_t *files, enum STYLE style, off_t off) { - int active, ev_change, i, n = -1; + int active, ev_change, i, n; struct stat sb2; file_info_t *file; FILE *ftmp; struct timespec ts; /* Position each of the files */ - - file = files; active = 0; - n = 0; - for (i = 0; i < no_files; i++, file++) { - if (file->fp) { - active = 1; - n++; - if (vflag || (qflag == 0 && no_files > 1)) - printfn(file->file_name, 1); - forward(file->fp, file->file_name, style, off, &file->st); - if (Fflag && fileno(file->fp) != STDIN_FILENO) - n++; - } + for (i = 0, file = files; i < no_files; i++, file++) { + if (!file->fp) + continue; + active = 1; + if (vflag || (qflag == 0 && no_files > 1)) + printfn(file->file_name, 1); + forward(file->fp, file->file_name, style, off, &file->st); } if (!Fflag && !active) return; @@ -337,9 +331,14 @@ follow(file_info_t *files, enum STYLE style, off_t off) kq = kqueue(); if (kq < 0) err(1, "kqueue"); - ev = malloc(n * sizeof(struct kevent)); - if (! ev) - err(1, "Couldn't allocate memory for kevents."); + /* + * The number of kqueue events we track may vary over time and may + * even grow past its initial value in the -F case, but it will + * never exceed two per file, so just preallocate that. + */ + ev = malloc(no_files * 2 * sizeof(struct kevent)); + if (ev == NULL) + err(1, "failed to allocate memory for kevents"); set_events(files); for (;;) { @@ -413,9 +412,7 @@ follow(file_info_t *files, enum STYLE style, off_t off) */ do { n = kevent(kq, NULL, 0, ev, 1, Fflag ? &ts : NULL); - if (n < 0 && errno == EINTR) - continue; - if (n < 0) + if (n < 0 && errno != EINTR) err(1, "kevent"); } while (n < 0); if (n == 0) { diff --git a/usr.bin/tail/read.c b/usr.bin/tail/read.c index ff025b31d64c..67bc5750cd0b 100644 --- a/usr.bin/tail/read.c +++ b/usr.bin/tail/read.c @@ -72,7 +72,7 @@ bytes(FILE *fp, const char *fn, off_t off) char *sp; if ((sp = p = malloc(off)) == NULL) - err(1, "malloc"); + err(1, "failed to allocate memory"); for (wrap = 0, ep = p + off; (ch = getc(fp)) != EOF;) { *p = ch; @@ -146,7 +146,7 @@ lines(FILE *fp, const char *fn, off_t off) int blen, cnt, recno, wrap; if ((llines = calloc(off, sizeof(*llines))) == NULL) - err(1, "calloc"); + err(1, "failed to allocate memory"); p = sp = NULL; blen = cnt = recno = wrap = 0; rc = 0; @@ -154,7 +154,7 @@ lines(FILE *fp, const char *fn, off_t off) while ((ch = getc(fp)) != EOF) { if (++cnt > blen) { if ((sp = realloc(sp, blen += 1024)) == NULL) - err(1, "realloc"); + err(1, "failed to allocate memory"); p = sp + cnt - 1; } *p++ = ch; @@ -163,7 +163,7 @@ lines(FILE *fp, const char *fn, off_t off) llines[recno].blen = cnt + 256; if ((llines[recno].l = realloc(llines[recno].l, llines[recno].blen)) == NULL) - err(1, "realloc"); + err(1, "failed to allocate memory"); } bcopy(sp, llines[recno].l, llines[recno].len = cnt); cnt = 0; diff --git a/usr.bin/tail/reverse.c b/usr.bin/tail/reverse.c index 12231530e679..67d27d487d1c 100644 --- a/usr.bin/tail/reverse.c +++ b/usr.bin/tail/reverse.c @@ -212,7 +212,7 @@ r_buf(FILE *fp, const char *fn) while ((tl = malloc(sizeof(bfelem_t))) == NULL) { first = TAILQ_FIRST(&head); if (TAILQ_EMPTY(&head)) - err(1, "malloc"); + err(1, "failed to allocate memory"); enomem += first->len; TAILQ_REMOVE(&head, first, entries); free(first); diff --git a/usr.bin/tail/tail.c b/usr.bin/tail/tail.c index 492a6494628d..c206b11863a5 100644 --- a/usr.bin/tail/tail.c +++ b/usr.bin/tail/tail.c @@ -173,7 +173,7 @@ main(int argc, char *argv[]) cap_rights_set(&rights, CAP_EVENT); if (caph_rights_limit(STDIN_FILENO, &rights) < 0 || caph_limit_stderr() < 0 || caph_limit_stdout() < 0) - err(1, "can't limit stdio rights"); + err(1, "unable to limit stdio rights"); fa = fileargs_init(argc, argv, O_RDONLY, 0, &rights, FA_OPEN); if (fa == NULL) @@ -213,7 +213,7 @@ main(int argc, char *argv[]) if (*argv && fflag) { files = malloc(no_files * sizeof(struct file_info)); if (files == NULL) - err(1, "Couldn't malloc space for file descriptors."); + err(1, "failed to allocate memory for file descriptors"); for (filep = files; (fn = *argv++); filep++) { filep->file_name = fn; @@ -308,7 +308,7 @@ obsolete(char *argv[]) /* Malloc space for dash, new option and argument. */ len = strlen(*argv); if ((start = p = malloc(len + 3)) == NULL) - err(1, "malloc"); + err(1, "failed to allocate memory"); *p++ = '-'; /* diff --git a/usr.bin/tail/tests/tail_test.sh b/usr.bin/tail/tests/tail_test.sh index 8123a310fe67..9c941f8a2c2f 100755 --- a/usr.bin/tail/tests/tail_test.sh +++ b/usr.bin/tail/tests/tail_test.sh @@ -329,10 +329,28 @@ follow_stdin_body() atf_check kill $pid } +atf_test_case follow_create +follow_create_head() +{ + atf_set "descr" "Verify that -F works when a file is created" +} +follow_create_body() +{ + local pid + + rm -f infile + tail -F infile > outfile & + pid=$! + seq 1 5 >infile + sleep 2 + atf_check cmp infile outfile + atf_check kill $pid +} + atf_test_case follow_rename follow_rename_head() { - atf_set "descr" "Verify that -F works" + atf_set "descr" "Verify that -F works when a file is replaced" } follow_rename_body() { @@ -424,6 +442,7 @@ atf_init_test_cases() atf_add_test_case stdin atf_add_test_case follow atf_add_test_case follow_stdin + atf_add_test_case follow_create atf_add_test_case follow_rename atf_add_test_case silent_header atf_add_test_case verbose_header
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