From 5a28455359f06b45d47a4da33240888a44acdf46 Mon Sep 17 00:00:00 2001 From: George Dunlap Date: Wed, 11 Oct 2017 18:49:39 +0100 Subject: [PATCH] fuzz/x86_emulate: Implement input_read() and input_avail() Rather than open-coding the "read" from the input file. Signed-off-by: George Dunlap Acked-by: Andrew Cooper Reviewed-by: Ian Jackson --- .../fuzz/x86_instruction_emulator/fuzz-emul.c | 31 +++++++++++++------ 1 file changed, 22 insertions(+), 9 deletions(-) diff --git a/tools/fuzz/x86_instruction_emulator/fuzz-emul.c b/tools/fuzz/x86_instruction_emulator/fuzz-emul.c index 999f417716..5fb8586955 100644 --- a/tools/fuzz/x86_instruction_emulator/fuzz-emul.c +++ b/tools/fuzz/x86_instruction_emulator/fuzz-emul.c @@ -52,6 +52,22 @@ struct fuzz_state struct x86_emulate_ops ops; }; +static inline bool input_avail(const struct fuzz_state *s, size_t size) +{ + return s->data_index + size <= s->data_num; +} + +static inline bool input_read(struct fuzz_state *s, void *dst, size_t size) +{ + if ( !input_avail(s, size) ) + return false; + + memcpy(dst, &s->corpus->data[s->data_index], size); + s->data_index += size; + + return true; +} + static const char* const x86emul_return_string[] = { [X86EMUL_OKAY] = "X86EMUL_OKAY", [X86EMUL_UNHANDLEABLE] = "X86EMUL_UNHANDLEABLE", @@ -68,10 +84,10 @@ static int maybe_fail(struct x86_emulate_ctxt *ctxt, const char *why, bool exception) { struct fuzz_state *s = ctxt->data; - const struct fuzz_corpus *c = s->corpus; + unsigned char c; int rc; - if ( s->data_index >= s->data_num ) + if ( !input_read(s, &c, sizeof(c)) ) rc = X86EMUL_EXCEPTION; else { @@ -80,13 +96,12 @@ static int maybe_fail(struct x86_emulate_ctxt *ctxt, * 25% unhandlable * 25% exception */ - if ( c->data[s->data_index] > 0xc0 ) + if ( c > 0xc0 ) rc = X86EMUL_EXCEPTION; - else if ( c->data[s->data_index] > 0x80 ) + else if ( c > 0x80 ) rc = X86EMUL_UNHANDLEABLE; else rc = X86EMUL_OKAY; - s->data_index++; } if ( rc == X86EMUL_EXCEPTION && !exception ) @@ -106,11 +121,10 @@ static int data_read(struct x86_emulate_ctxt *ctxt, const char *why, void *dst, unsigned int bytes) { struct fuzz_state *s = ctxt->data; - const struct fuzz_corpus *c = s->corpus; unsigned int i; int rc; - if ( s->data_index + bytes > s->data_num ) + if ( !input_avail(s, bytes) ) { /* * Fake up a segment limit violation. System segment limit volations @@ -128,8 +142,7 @@ static int data_read(struct x86_emulate_ctxt *ctxt, if ( rc == X86EMUL_OKAY ) { - memcpy(dst, &c->data[s->data_index], bytes); - s->data_index += bytes; + input_read(s, dst, bytes); printf("%s: ", why); for ( i = 0; i < bytes; i++ ) -- 2.39.5