krb5 commit: Fix two unlikely memory leaks
ghudson at mit.edu
ghudson at mit.edu
Tue Mar 19 10:54:04 EDT 2024
https://github.com/krb5/krb5/commit/c5f9c816107f70139de11b38aa02db2f1774ee0d
commit c5f9c816107f70139de11b38aa02db2f1774ee0d
Author: Greg Hudson <ghudson at mit.edu>
Date: Tue Mar 5 19:53:07 2024 -0500
Fix two unlikely memory leaks
In gss_krb5int_make_seal_token_v3(), one of the bounds checks (which
could probably never be triggered) leaks plain.data. Fix this leak
and use current practices for cleanup throughout the function.
In xmt_rmtcallres() (unused within the tree and likely elsewhere),
store port_ptr into crp->port_ptr as soon as it is allocated;
otherwise it could leak if the subsequent xdr_u_int32() operation
fails.
src/lib/gssapi/krb5/k5sealv3.c | 56 ++++++++++++++++++------------------------
src/lib/rpc/pmap_rmt.c | 10 ++++----
2 files changed, 29 insertions(+), 37 deletions(-)
diff --git a/src/lib/gssapi/krb5/k5sealv3.c b/src/lib/gssapi/krb5/k5sealv3.c
index 3b4f8cb83..e881eee83 100644
--- a/src/lib/gssapi/krb5/k5sealv3.c
+++ b/src/lib/gssapi/krb5/k5sealv3.c
@@ -65,7 +65,7 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
int conf_req_flag, int toktype)
{
size_t bufsize = 16;
- unsigned char *outbuf = 0;
+ unsigned char *outbuf = NULL;
krb5_error_code err;
int key_usage;
unsigned char acceptor_flag;
@@ -75,9 +75,13 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
#endif
size_t ec;
unsigned short tok_id;
- krb5_checksum sum;
+ krb5_checksum sum = { 0 };
krb5_key key;
krb5_cksumtype cksumtype;
+ krb5_data plain = empty_data();
+
+ token->value = NULL;
+ token->length = 0;
acceptor_flag = ctx->initiate ? 0 : FLAG_SENDER_IS_ACCEPTOR;
key_usage = (toktype == KG_TOK_WRAP_MSG
@@ -107,14 +111,15 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
#endif
if (toktype == KG_TOK_WRAP_MSG && conf_req_flag) {
- krb5_data plain;
krb5_enc_data cipher;
size_t ec_max;
size_t encrypt_size;
/* 300: Adds some slop. */
- if (SIZE_MAX - 300 < message->length)
- return ENOMEM;
+ if (SIZE_MAX - 300 < message->length) {
+ err = ENOMEM;
+ goto cleanup;
+ }
ec_max = SIZE_MAX - message->length - 300;
if (ec_max > 0xffff)
ec_max = 0xffff;
@@ -126,20 +131,20 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
#endif
err = alloc_data(&plain, message->length + 16 + ec);
if (err)
- return err;
+ goto cleanup;
/* Get size of ciphertext. */
encrypt_size = krb5_encrypt_size(plain.length, key->keyblock.enctype);
if (encrypt_size > SIZE_MAX / 2) {
err = ENOMEM;
- goto error;
+ goto cleanup;
}
bufsize = 16 + encrypt_size;
/* Allocate space for header plus encrypted data. */
outbuf = gssalloc_malloc(bufsize);
if (outbuf == NULL) {
- free(plain.data);
- return ENOMEM;
+ err = ENOMEM;
+ goto cleanup;
}
/* TOK_ID */
@@ -164,11 +169,8 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
cipher.ciphertext.length = bufsize - 16;
cipher.enctype = key->keyblock.enctype;
err = krb5_k_encrypt(context, key, key_usage, 0, &plain, &cipher);
- zap(plain.data, plain.length);
- free(plain.data);
- plain.data = 0;
if (err)
- goto error;
+ goto cleanup;
/* Now that we know we're returning a valid token.... */
ctx->seq_send++;
@@ -181,7 +183,6 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
/* If the rotate fails, don't worry about it. */
#endif
} else if (toktype == KG_TOK_WRAP_MSG && !conf_req_flag) {
- krb5_data plain;
size_t cksumsize;
/* Here, message is the application-supplied data; message2 is
@@ -193,21 +194,19 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
wrap_with_checksum:
err = alloc_data(&plain, message->length + 16);
if (err)
- return err;
+ goto cleanup;
err = krb5_c_checksum_length(context, cksumtype, &cksumsize);
if (err)
- goto error;
+ goto cleanup;
assert(cksumsize <= 0xffff);
bufsize = 16 + message2->length + cksumsize;
outbuf = gssalloc_malloc(bufsize);
if (outbuf == NULL) {
- free(plain.data);
- plain.data = 0;
err = ENOMEM;
- goto error;
+ goto cleanup;
}
/* TOK_ID */
@@ -239,23 +238,15 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
if (message2->length)
memcpy(outbuf + 16, message2->value, message2->length);
- sum.contents = outbuf + 16 + message2->length;
- sum.length = cksumsize;
-
err = krb5_k_make_checksum(context, cksumtype, key,
key_usage, &plain, &sum);
- zap(plain.data, plain.length);
- free(plain.data);
- plain.data = 0;
if (err) {
zap(outbuf,bufsize);
- goto error;
+ goto cleanup;
}
if (sum.length != cksumsize)
abort();
memcpy(outbuf + 16 + message2->length, sum.contents, cksumsize);
- krb5_free_checksum_contents(context, &sum);
- sum.contents = 0;
/* Now that we know we're actually generating the token... */
ctx->seq_send++;
@@ -285,12 +276,13 @@ gss_krb5int_make_seal_token_v3 (krb5_context context,
token->value = outbuf;
token->length = bufsize;
- return 0;
+ outbuf = NULL;
+ err = 0;
-error:
+cleanup:
+ krb5_free_checksum_contents(context, &sum);
+ zapfree(plain.data, plain.length);
gssalloc_free(outbuf);
- token->value = NULL;
- token->length = 0;
return err;
}
diff --git a/src/lib/rpc/pmap_rmt.c b/src/lib/rpc/pmap_rmt.c
index 434e4eea6..f55ca46c6 100644
--- a/src/lib/rpc/pmap_rmt.c
+++ b/src/lib/rpc/pmap_rmt.c
@@ -161,12 +161,12 @@ xdr_rmtcallres(
caddr_t port_ptr;
port_ptr = (caddr_t)(void *)crp->port_ptr;
- if (xdr_reference(xdrs, &port_ptr, sizeof (uint32_t),
- (xdrproc_t)xdr_u_int32) &&
- xdr_u_int32(xdrs, &crp->resultslen)) {
- crp->port_ptr = (uint32_t *)(void *)port_ptr;
+ if (!xdr_reference(xdrs, &port_ptr, sizeof (uint32_t),
+ (xdrproc_t)xdr_u_int32))
+ return (FALSE);
+ crp->port_ptr = (uint32_t *)(void *)port_ptr;
+ if (xdr_u_int32(xdrs, &crp->resultslen))
return ((*(crp->xdr_results))(xdrs, crp->results_ptr));
- }
return (FALSE);
}
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