This patch checks the depth of nested parentheses to prevent stack overflow.
Reported-at: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=10714 Signed-off-by: Yifeng Sun <pkusunyif...@gmail.com> Suggested-by: Ben Pfaff <b...@ovn.org> --- v1->v2: Handle parse_chassis_resident and add new test, thanks Ben! ovn/lib/expr.c | 17 +++++++++++++++++ tests/ovn.at | 5 +++++ 2 files changed, 22 insertions(+) diff --git a/ovn/lib/expr.c b/ovn/lib/expr.c index 148ac869e861..96e61606e288 100644 --- a/ovn/lib/expr.c +++ b/ovn/lib/expr.c @@ -459,6 +459,8 @@ expr_print(const struct expr *e) /* Parsing. */ +#define MAX_PAREN_DEPTH 100 + /* Context maintained during expr_parse(). */ struct expr_context { struct lexer *lexer; /* Lexer for pulling more tokens. */ @@ -466,6 +468,7 @@ struct expr_context { const struct shash *addr_sets; /* Address set table. */ const struct shash *port_groups; /* Port group table. */ bool not; /* True inside odd number of NOT operators. */ + unsigned int paren_depth; /* Depth of nested parentheses. */ }; struct expr *expr_parse__(struct expr_context *); @@ -1068,6 +1071,7 @@ parse_chassis_resident(struct expr_context *ctx) expr_destroy(e); return NULL; } + --ctx->paren_depth; return e; } @@ -1077,11 +1081,18 @@ expr_parse_primary(struct expr_context *ctx, bool *atomic) { *atomic = false; if (lexer_match(ctx->lexer, LEX_T_LPAREN)) { + if (++ctx->paren_depth > MAX_PAREN_DEPTH) { + lexer_syntax_error(ctx->lexer, + "parenthesis nested too deeply"); + return NULL; + } + struct expr *e = expr_parse__(ctx); if (!lexer_force_match(ctx->lexer, LEX_T_RPAREN)) { expr_destroy(e); return NULL; } + --ctx->paren_depth; *atomic = true; return e; } @@ -1093,6 +1104,12 @@ expr_parse_primary(struct expr_context *ctx, bool *atomic) if (lexer_lookahead(ctx->lexer) == LEX_T_LPAREN) { if (lexer_match_id(ctx->lexer, "is_chassis_resident")) { + if (++ctx->paren_depth > MAX_PAREN_DEPTH) { + lexer_syntax_error(ctx->lexer, + "parenthesis nested too deeply"); + return NULL; + } + lexer_get(ctx->lexer); /* Skip "(". */ *atomic = true; return parse_chassis_resident(ctx); diff --git a/tests/ovn.at b/tests/ovn.at index 44475175d20a..584fb5c2a727 100644 --- a/tests/ovn.at +++ b/tests/ovn.at @@ -285,6 +285,8 @@ ip6.src == ::1 => ip6.src == 0x1 inport == "eth0" !(inport != "eth0") => inport == "eth0" +(((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((is_chassis_resident("eth0")))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))) => is_chassis_resident("eth0") + ip4.src == "eth0" => Integer field ip4.src is not compatible with string constant. inport == 1 => String field inport is not compatible with integer constant. ip4.src = 1.2.3.4 => Syntax error at `=' expecting relational operator. @@ -351,6 +353,9 @@ eth.dst[40] x => Syntax error at `x' expecting end of input. ip4.src == {1.2.3.4, $set1, $unknownset} => Syntax error at `$unknownset' expecting address set name. eth.src == {$set3, badmac, 00:00:00:00:00:01} => Syntax error at `badmac' expecting constant. + +((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((( => Syntax error at end of input parenthesis nested too deeply. +((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((((is_chassis_resident("eth1") => Syntax error at `(' parenthesis nested too deeply. ]]) sed 's/ =>.*//' test-cases.txt > input.txt sed 's/.* => //' test-cases.txt > expout -- 2.7.4 _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
