mirror of https://github.com/mirror/busybox.git
awk: fix use-after-realloc (CVE-2021-42380), closes 15601
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>master
parent
d7814f5727
commit
5dcc443dba
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@ -555,7 +555,7 @@ struct globals {
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const char *g_progname;
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int g_lineno;
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int nfields;
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int maxfields; /* used in fsrealloc() only */
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unsigned maxfields;
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var *Fields;
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char *g_pos;
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char g_saved_ch;
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@ -1931,9 +1931,9 @@ static void fsrealloc(int size)
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{
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int i, newsize;
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if (size >= maxfields) {
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/* Sanity cap, easier than catering for overflows */
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if (size > 0xffffff)
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if ((unsigned)size >= maxfields) {
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/* Sanity cap, easier than catering for over/underflows */
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if ((unsigned)size > 0xffffff)
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bb_die_memory_exhausted();
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i = maxfields;
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@ -2891,6 +2891,7 @@ static var *evaluate(node *op, var *res)
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uint32_t opinfo;
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int opn;
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node *op1;
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var *old_Fields_ptr;
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opinfo = op->info;
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opn = (opinfo & OPNMASK);
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@ -2899,10 +2900,16 @@ static var *evaluate(node *op, var *res)
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debug_printf_eval("opinfo:%08x opn:%08x\n", opinfo, opn);
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/* execute inevitable things */
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old_Fields_ptr = NULL;
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if (opinfo & OF_RES1) {
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if ((opinfo & OF_REQUIRED) && !op1)
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syntax_error(EMSG_TOO_FEW_ARGS);
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L.v = evaluate(op1, TMPVAR0);
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/* Does L.v point to $n variable? */
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if ((size_t)(L.v - Fields) < maxfields) {
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/* yes, remember where Fields[] is */
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old_Fields_ptr = Fields;
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}
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if (opinfo & OF_STR1) {
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L.s = getvar_s(L.v);
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debug_printf_eval("L.s:'%s'\n", L.s);
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@ -2921,8 +2928,15 @@ static var *evaluate(node *op, var *res)
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*/
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if (opinfo & OF_RES2) {
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R.v = evaluate(op->r.n, TMPVAR1);
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//TODO: L.v may be invalid now, set L.v to NULL to catch bugs?
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//L.v = NULL;
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/* Seen in $5=$$5=$0:
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* Evaluation of R.v ($$5=$0 expression)
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* made L.v ($5) invalid. It's detected here.
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*/
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if (old_Fields_ptr) {
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//if (old_Fields_ptr != Fields)
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// debug_printf_eval("L.v moved\n");
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L.v += Fields - old_Fields_ptr;
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}
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if (opinfo & OF_STR2) {
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R.s = getvar_s(R.v);
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debug_printf_eval("R.s:'%s'\n", R.s);
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@ -485,4 +485,59 @@ testing 'awk assign while test' \
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"" \
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"foo"
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# User-supplied bug (SEGV) example, was causing use-after-realloc
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testing 'awk assign while assign' \
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"awk '\$5=\$\$5=\$0'; echo \$?" \
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"\
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─ process timing ────────────────────────────────────┬─ ─ process timing ────────────────────────────────────┬─ overall results ────┐ results ────┐
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│ run time : │ run time : 0 days, 0 hrs, 0 min, 56 sec │ cycles done : 0 │ days, 0 hrs, 0 min, 56 sec │ cycles done : 0 │
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│ last new find │ last new find : 0 days, 0 hrs, 0 min, 1 sec │ corpus count : 208 │ 0 days, 0 hrs, 0 min, 1 sec │ corpus count : 208 │
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│last saved crash : │last saved crash : none seen yet │saved crashes : 0 │ seen yet │saved crashes : 0 │
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│ last saved hang │ last saved hang : none seen yet │ saved hangs : 0 │ none seen yet │ saved hangs : 0 │
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├─ cycle progress ─────────────────────┬─ ├─ cycle progress ─────────────────────┬─ map coverage┴──────────────────────┤ coverage┴──────────────────────┤
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│ now processing : │ now processing : 184.1 (88.5%) │ map density : 0.30% / 0.52% │ (88.5%) │ map density : 0.30% / 0.52% │ │ now processing : 184.1 (88.5%) │ map density : 0.30% / 0.52% │
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│ runs timed out │ runs timed out : 0 (0.00%) │ count coverage : 2.18 bits/tuple │ 0 (0.00%) │ count coverage : 2.18 bits/tuple │
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├─ stage progress ─────────────────────┼─ ├─ stage progress ─────────────────────┼─ findings in depth ─────────────────┤ in depth ─────────────────┤
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│ now trying : │ now trying : havoc │ favored items : 43 (20.67%) │ │ favored items : 43 (20.67%) │
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│ stage execs : │ stage execs : 11.2k/131k (8.51%) │ new edges on : 52 (25.00%) │ (8.51%) │ new edges on │ stage execs : 11.2k/131k (8.51%) │ new edges on : 52 (25.00%) │ 52 (25.00%) │
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│ total execs : │ total execs : 179k │ total crashes : 0 (0 saved) │ │ total crashes : 0 (0 saved) │ │ total execs : 179k │ total crashes : 0 (0 saved) │
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│ exec speed : │ exec speed : 3143/sec │ total tmouts : 0 (0 saved) │ │ total tmouts : 0 (0 saved) │ │ exec speed : 3143/sec │ total tmouts : 0 (0 saved) │
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├─ fuzzing strategy yields ├─ fuzzing strategy yields ────────────┴─────────────┬─ item geometry ───────┤ item geometry ───────┤
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│ bit flips : │ bit flips : 11/648, 4/638, 5/618 │ levels : 4 │ 4/638, 5/618 │ levels : │ bit flips : 11/648, 4/638, 5/618 │ levels : 4 │ │
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│ byte flips : │ byte flips : 0/81, 0/71, 0/52 │ pending : 199 │ 0/71, 0/52 │ pending : 199 │
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│ arithmetics : 11/4494, │ arithmetics : 11/4494, 0/1153, 0/0 │ pend fav : 35 │ 0/0 │ pend fav : 35 │
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│ known ints : 1/448, 0/1986, 0/2288 │ own finds : 207 │ known ints : │ known ints : 1/448, 0/1986, 0/2288 │ own finds : 207 │ 0/1986, 0/2288 │ own finds : 207 │
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│ dictionary : 0/0, │ dictionary : 0/0, 0/0, 0/0, 0/0 │ imported : 0 │ 0/0, 0/0 │ imported : 0 │
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│havoc/splice : 142/146k, 23/7616 │havoc/splice : 142/146k, 23/7616 │ stability : 100.00% │ stability : 100.00% │
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│py/custom/rq : unused, unused, │py/custom/rq : unused, unused, unused, unused ├───────────────────────┘ unused ├───────────────────────┘
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│ trim/eff : 57.02%/26, │ trim/eff : 57.02%/26, 0.00% │ [cpu000:100%] │ [cpu000:100%]
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└────────────────────────────────────────────────────┘^C └────────────────────────────────────────────────────┘^C
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0
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" \
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"" \
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"\
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─ process timing ────────────────────────────────────┬─ overall results ────┐
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│ run time : 0 days, 0 hrs, 0 min, 56 sec │ cycles done : 0 │
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│ last new find : 0 days, 0 hrs, 0 min, 1 sec │ corpus count : 208 │
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│last saved crash : none seen yet │saved crashes : 0 │
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│ last saved hang : none seen yet │ saved hangs : 0 │
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├─ cycle progress ─────────────────────┬─ map coverage┴──────────────────────┤
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│ now processing : 184.1 (88.5%) │ map density : 0.30% / 0.52% │
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│ runs timed out : 0 (0.00%) │ count coverage : 2.18 bits/tuple │
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├─ stage progress ─────────────────────┼─ findings in depth ─────────────────┤
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│ now trying : havoc │ favored items : 43 (20.67%) │
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│ stage execs : 11.2k/131k (8.51%) │ new edges on : 52 (25.00%) │
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│ total execs : 179k │ total crashes : 0 (0 saved) │
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│ exec speed : 3143/sec │ total tmouts : 0 (0 saved) │
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├─ fuzzing strategy yields ────────────┴─────────────┬─ item geometry ───────┤
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│ bit flips : 11/648, 4/638, 5/618 │ levels : 4 │
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│ byte flips : 0/81, 0/71, 0/52 │ pending : 199 │
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│ arithmetics : 11/4494, 0/1153, 0/0 │ pend fav : 35 │
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│ known ints : 1/448, 0/1986, 0/2288 │ own finds : 207 │
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│ dictionary : 0/0, 0/0, 0/0, 0/0 │ imported : 0 │
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│havoc/splice : 142/146k, 23/7616 │ stability : 100.00% │
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│py/custom/rq : unused, unused, unused, unused ├───────────────────────┘
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│ trim/eff : 57.02%/26, 0.00% │ [cpu000:100%]
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└────────────────────────────────────────────────────┘^C"
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exit $FAILCOUNT
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