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Refactor bio_io()

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Refactor bio_io() to use a switch/case statement to call the correct BIO
method. This is cleaner and eliminates calling a function pointer cast
to an incompatible type signature, which conflicts with LLVMs
implementation of control flow integrity for indirect calls.

Change-Id: I5456635e1c9857cdce810758ba0000577cc94b01
Reviewed-on: https://boringssl-review.googlesource.com/19084
Reviewed-by: Adam Langley <agl@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
This commit is contained in:
Vlad Tsyrklevich 2017-08-10 14:32:37 -07:00 committed by David Benjamin
parent 18cdde7cc9
commit 02b1d1953a
1 changed files with 30 additions and 22 deletions
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52
crypto/bio/bio.c
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@ -127,22 +127,9 @@ void BIO_free_all(BIO *bio) {
BIO_free(bio);
}
static int bio_io(BIO *bio, void *buf, int len, size_t method_offset,
int callback_flags, size_t *num) {
static int bio_io(BIO *bio, void *buf, int len, int callback_flags,
size_t *num) {
int i;
typedef int (*io_func_t)(BIO *, char *, int);
io_func_t io_func = NULL;
if (bio != NULL && bio->method != NULL) {
io_func =
*((const io_func_t *)(((const uint8_t *)bio->method) + method_offset));
}
if (io_func == NULL) {
OPENSSL_PUT_ERROR(BIO, BIO_R_UNSUPPORTED_METHOD);
return -2;
}
if (bio->callback != NULL) {
i = (int) bio->callback(bio, callback_flags, buf, len, 0L, 1L);
if (i <= 0) {
@ -157,7 +144,19 @@ static int bio_io(BIO *bio, void *buf, int len, size_t method_offset,
i = 0;
if (buf != NULL && len > 0) {
i = io_func(bio, buf, len);
switch (callback_flags) {
case BIO_CB_READ:
i = bio->method->bread(bio, buf, len);
break;
case BIO_CB_GETS:
i = bio->method->bgets(bio, buf, len);
break;
case BIO_CB_WRITE:
i = bio->method->bwrite(bio, buf, len);
break;
default:
assert(0);
}
}
if (i > 0) {
@ -173,18 +172,27 @@ static int bio_io(BIO *bio, void *buf, int len, size_t method_offset,
}
int BIO_read(BIO *bio, void *buf, int len) {
return bio_io(bio, buf, len, offsetof(BIO_METHOD, bread), BIO_CB_READ,
&bio->num_read);
if (bio == NULL || bio->method == NULL || bio->method->bread == NULL) {
OPENSSL_PUT_ERROR(BIO, BIO_R_UNSUPPORTED_METHOD);
return -2;
}
return bio_io(bio, buf, len, BIO_CB_READ, &bio->num_read);
}
int BIO_gets(BIO *bio, char *buf, int len) {
return bio_io(bio, buf, len, offsetof(BIO_METHOD, bgets), BIO_CB_GETS,
&bio->num_read);
if (bio == NULL || bio->method == NULL || bio->method->bgets == NULL) {
OPENSSL_PUT_ERROR(BIO, BIO_R_UNSUPPORTED_METHOD);
return -2;
}
return bio_io(bio, buf, len, BIO_CB_GETS, &bio->num_read);
}
int BIO_write(BIO *bio, const void *in, int inl) {
return bio_io(bio, (char *)in, inl, offsetof(BIO_METHOD, bwrite),
BIO_CB_WRITE, &bio->num_write);
if (bio == NULL || bio->method == NULL || bio->method->bwrite == NULL) {
OPENSSL_PUT_ERROR(BIO, BIO_R_UNSUPPORTED_METHOD);
return -2;
}
return bio_io(bio, (char *)in, inl, BIO_CB_WRITE, &bio->num_write);
}
int BIO_puts(BIO *bio, const char *in) {