rpms/libkcapi
7
0
Fork 0
Code Issues Pull Requests Releases Activity

Add tag processing in AEAD decryption without ciphertext

Browse Source 
Resolves: RHEL-242667

Signed-off-by: Zoltan Fridrich <zfridric@redhat.com>
This commit is contained in:
Zoltan Fridrich 2026-08-18 11:42:21 +02:00
parent 8a3bf3733b
commit 8f8ae89566
2 changed files with 107 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

104
006-aead-tag-verification.patch Normal file
View File

@ -0,0 +1,104 @@
diff --git a/apps/kcapi-enc.c b/apps/kcapi-enc.c
index e7aa9db..0ca7c19 100644
--- a/apps/kcapi-enc.c
+++ b/apps/kcapi-enc.c
@@ -608,7 +608,7 @@ static int cipher_op(struct kcapi_handle *handle, struct opt_data *opts)
}
/* Get data from file. */
- } else {
+ } else if (insb.st_size) {
uint32_t sent_data = 0;
inmem = mmap(NULL, (size_t)insb.st_size, PROT_READ, MAP_SHARED,
@@ -704,6 +704,27 @@ static int cipher_op(struct kcapi_handle *handle, struct opt_data *opts)
}
}
+ /* AEAD with no input. Still generate/verify the tag */
+ if (opts->aad && !generated_bytes) {
+ outsize = outbufsize(handle, opts, 0);
+
+ ret = sendtag(handle, opts, tagbuf, tagtmpbuf);
+ if (ret)
+ goto out;
+
+ if (outfd != STDOUT_FD) {
+ ret = ftruncate(outfd, (off_t)outsize);
+ if (ret)
+ goto out;
+ }
+
+ ret = return_data(handle, opts, outfd, outsize, 0, 0);
+ if (ret < 0)
+ goto out;
+
+ generated_bytes += (unsigned int)ret;
+ }
+
out:
if (inmem && inmem != MAP_FAILED)
munmap(inmem, (size_t)insb.st_size);
diff --git a/test/kcapi-enc-test.sh b/test/kcapi-enc-test.sh
index 1686302..37d3448 100755
--- a/test/kcapi-enc-test.sh
+++ b/test/kcapi-enc-test.sh
@@ -321,9 +321,58 @@ test_gcm_enc()
fi
}
+test_aead_zero_len()
+{
+ local aadlen=${#GCM_AAD}
+
+ aadlen=$(($aadlen/2))
+
+ : > ${TSTPREFIX}empty
+
+ # Encrypt zero-length plaintext
+ exec 10<${TSTPREFIX}gcm_key; run_app kcapi-enc --keyfd 10 -e -c "gcm(aes)" -i ${TSTPREFIX}empty -o ${TSTPREFIX}gcm_zero_ct --iv $GCM_IV --aad $GCM_AAD --taglen $GCM_TAGLEN
+ if [ $? -ne 0 ]
+ then
+ echo_fail "AEAD zero-length encryption failed"
+ return
+ fi
+
+ local ctsize=$(stat -c %s ${TSTPREFIX}gcm_zero_ct)
+ if [ $ctsize -eq 0 ]
+ then
+ echo_fail "AEAD zero-length encryption produced no output"
+ return
+ fi
+ echo_pass "AEAD zero-length GCM encrypt"
+
+ # Extract the tag from the encryption output
+ local tag=$(bin2hex_noaad ${TSTPREFIX}gcm_zero_ct $aadlen)
+
+ # Decrypt zero-length ciphertext with correct tag
+ exec 10<${TSTPREFIX}gcm_key; run_app kcapi-enc --keyfd 10 -d -c "gcm(aes)" -i ${TSTPREFIX}empty -o ${TSTPREFIX}gcm_zero_pt --iv $GCM_IV --aad $GCM_AAD --tag $tag
+ if [ $? -ne 0 ]
+ then
+ echo_fail "AEAD zero-length decryption with valid tag failed"
+ return
+ fi
+ echo_pass "AEAD zero-length GCM decrypt with valid tag"
+
+ # Decrypt zero-length ciphertext with wrong tag - must fail
+ exec 10<${TSTPREFIX}gcm_key; run_app kcapi-enc --keyfd 10 -d -c "gcm(aes)" -i ${TSTPREFIX}empty -o ${TSTPREFIX}gcm_zero_pt --iv $GCM_IV --aad $GCM_AAD --tag 00000000000000000000000000000000 -q
+
+ # 182 == -EBADMSG
+ if [ $? -eq 182 ]
+ then
+ echo_pass "AEAD zero-length GCM decrypt integrity violation"
+ else
+ echo_fail "AEAD zero-length GCM decrypt integrity violation not caught"
+ fi
+}
+
init_setup
test_gcm_enc
test_ccm_dec
+test_aead_zero_len
for i in 1 15 16 29 32 257 512 1023 16385 65535 65536 65537 99999 100000 100001
do

3
libkcapi.spec
View File

@ -138,6 +138,7 @@ Patch2: 002-remove-ansi_cprng-test.patch
Patch3: 003-zeroize-hasher.patch
Patch4: 004-hasher-target-option.patch
Patch5: 005-fips-mode-tests.patch
Patch6: 006-aead-tag-verification.patch
BuildRequires: bash
BuildRequires: coreutils
@ -523,6 +524,8 @@ popd
* Tue Aug 18 2026 Zoltan Fridrich <zfridric@redhat.com> - 1.4.0-3
- Remove ansi_cprng test as new kernels don't support it
Resolves: RHEL-242707
- Add tag processing in AEAD decryption without ciphertext
Resolves: RHEL-242667
* Fri Dec 01 2023 Zoltan Fridrich <zfridric@redhat.com> - 1.4.0-2
- Backport fixes for kcapi-hasher target option