added checks to avoid overflows caused by user supplied field sizes

This commit is contained in:
git@daemon.de
2015-06-26 11:13:03 +02:00
parent 9b3202df5c
commit 0dbf5df943
2 changed files with 37 additions and 16 deletions

View File

@@ -145,7 +145,7 @@ size_t pcp_decrypt_stream(PCPCTX *ptx, Pcpstream *in, Pcpstream* out, pcp_key_t
else {
/* step 1, check header */
cur_bufsize = ps_read(in, head, 1); /* fread(head, 1, 1, in); */
if(cur_bufsize != 1 && !ps_end(in) && !ps_err(in)) {
if(cur_bufsize == 1 && !ps_end(in) && !ps_err(in)) {
if(head[0] == PCP_SYM_CIPHER) {
if(symkey != NULL)
self = 1;
@@ -206,7 +206,8 @@ size_t pcp_decrypt_stream(PCPCTX *ptx, Pcpstream *in, Pcpstream* out, pcp_key_t
for(nrec=0; nrec<lenrec; nrec++) {
cur_bufsize = ps_read(in, rec_buf, PCP_ASYM_RECIPIENT_SIZE);
if(cur_bufsize != PCP_ASYM_RECIPIENT_SIZE && !ps_end(in) && !ps_err(in)) {
fatal(ptx, "Error: input file corrupted, incomplete or no recipients (got %ld, exp %ld)\n", cur_bufsize, PCP_ASYM_RECIPIENT_SIZE );
fatal(ptx, "Error: input file corrupted, incomplete or no recipients (got %ld, exp %ld)\n",
cur_bufsize, PCP_ASYM_RECIPIENT_SIZE );
ucfree(rec_buf, PCP_ASYM_RECIPIENT_SIZE);
goto errdef1;
}
@@ -692,6 +693,12 @@ uint64_t _get_nonce_ctr(byte *nonce) {
uint16_t m16 = 0;
uint32_t m32 = 0;
if(i > 16) {
/* counter bigger than max allowed by protocol, could lead to overflow, therefore die hard here */
fprintf(stderr, "invalid counter size %d!", i);
abort();
}
switch(i) {
case 1:
ctr = nonce[1];

View File

@@ -70,6 +70,9 @@ int _check_keysig_h(PCPCTX *ptx, Buffer *blob, rfc_pub_sig_h *h) {
}
int _check_sigsubs(PCPCTX *ptx, Buffer *blob, pcp_pubkey_t *p, rfc_pub_sig_s *subheader) {
uint16_t nsize, vsize;
char *notation = NULL;
if(subheader->size > buffer_left(blob)) {
fatal(ptx, "Invalid header size %ld specified in source\n", subheader->size);
return 1;
@@ -77,44 +80,44 @@ int _check_sigsubs(PCPCTX *ptx, Buffer *blob, pcp_pubkey_t *p, rfc_pub_sig_s *su
if(subheader->type == EXP_SIG_SUB_NOTATION) {
/* mail or owner */
uint16_t nsize = buffer_get16na(blob);
uint16_t vsize = buffer_get16na(blob);
char *notation = ucmalloc(nsize+1);
nsize = buffer_get16na(blob);
vsize = buffer_get16na(blob);
if(nsize > buffer_left(blob)) {
fatal(ptx, "Invalid notation size %ld specified in source\n", nsize);
return 1;
}
notation = ucmalloc(nsize+1);
if(buffer_get_chunk(blob, notation, nsize) == 0) {
fatal(ptx, "Invalid notation size, expected %ld bytes, but got 0\n", nsize);
return 1;
goto sgcerr;
}
notation[nsize] = '\0';
if(vsize > buffer_left(blob)) {
if(vsize > buffer_left(blob) || vsize > 255) {
fatal(ptx, "Invalid notation value size %ld specified in source\n", vsize);
return 1;
goto sgcerr;
}
if(strncmp(notation, "owner", 5) == 0) {
if(buffer_get_chunk(blob, p->owner, vsize) == 0) {
fatal(ptx, "Invalid 'owner' notation, expected %ld bytes, but got 0\n", vsize);
return 1;
goto sgcerr;
}
}
else if(strncmp(notation, "mail", 4) == 0) {
if(buffer_get_chunk(blob, p->mail, vsize) == 0) {
fatal(ptx, "Invalid 'mail' notation, expected %ld bytes, but got 0\n", vsize);
return 1;
goto sgcerr;
}
}
else if(strncmp(notation, "serial", 6) == 0) {
p->serial = buffer_get32na(blob);
}
ucfree(notation, nsize);
ucfree(notation, nsize+1);
}
else {
/* unsupported or ignored sig subs:
@@ -129,8 +132,11 @@ int _check_sigsubs(PCPCTX *ptx, Buffer *blob, pcp_pubkey_t *p, rfc_pub_sig_s *su
}
}
return 0;
sgcerr:
ucfree(notation, nsize+1);
return 1;
}
int _check_hash_keysig(PCPCTX *ptx, Buffer *blob, pcp_pubkey_t *p, pcp_keysig_t *sk) {
@@ -814,7 +820,7 @@ pcp_key_t *pcp_import_secret_native(PCPCTX *ptx, Buffer *cipher, char *passphras
byte *symkey = NULL;
byte *clear = NULL;
size_t cipherlen = 0;
size_t minlen = (64 * 2) + (32 * 4) + 8 + 4 + 4;
size_t minlen = (64 * 2) + (32 * 4) + 8 + 4 + 4; /* key material and mandatory field sizes */
uint16_t notationlen = 0;
Buffer *blob = buffer_new(512, "secretdecryptbuf");
@@ -853,11 +859,19 @@ pcp_key_t *pcp_import_secret_native(PCPCTX *ptx, Buffer *cipher, char *passphras
buffer_get_chunk(blob, sk->edpub, 32);
notationlen = buffer_get16na(blob);
if(notationlen > 0)
if(notationlen > 255) {
fatal(ptx, "Invalid notation value size for owner\n");
goto impserr2;
}
else if(notationlen > 0)
buffer_get_chunk(blob, sk->owner, notationlen);
notationlen = buffer_get16na(blob);
if(notationlen > 0)
if(notationlen > 255) {
fatal(ptx, "Invalid notation value size for mail\n");
goto impserr2;
}
else if(notationlen > 0)
buffer_get_chunk(blob, sk->mail, notationlen);
if(buffer_done(blob) == 1)