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Fix GetSafeContent to check length #10018

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Merged
dgarske merged 2 commits into from
Mar 20, 2026
Merged

Fix GetSafeContent to check length #10018

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e0a19a7
Fix GetSafeContent to check length
embhorn Mar 19, 2026
b4d2cd6
Fix feedback from review
embhorn Mar 19, 2026
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36 changes: 36 additions & 0 deletions tests/api/test_pkcs12.c
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Original file line number Diff line number Diff line change
Expand Up @@ -235,3 +235,39 @@ int test_wc_d2i_PKCS12_bad_mac_salt(void)
return EXPECT_RESULT();
}

/* Test that a crafted PKCS12 with a ContentInfo SEQUENCE length smaller than
* the contained OID is rejected, rather than causing an integer underflow
* in ci->dataSz calculation. */
int test_wc_d2i_PKCS12_oid_underflow(void)
{
EXPECT_DECLS;
#if !defined(NO_ASN) && !defined(NO_PWDBASED) && defined(HAVE_PKCS12)
WC_PKCS12* pkcs12 = NULL;

/* Crafted PKCS12 DER: the inner ContentInfo SEQUENCE declares length 5,
* but contains a valid OID (1.2.840.113549.1.7.1) that is 11 bytes
* on the wire (tag 06 + length 09 + 9 value bytes). Without the bounds
* check, (word32)curSz - (localIdx - curIdx) = 5 - 11 underflows
* to ~4GB. */
static const byte crafted[] = {
0x30, 0x23, /* outer SEQ */
0x02, 0x01, 0x03, /* version 3 */
0x30, 0x1E, /* AuthSafe wrapper SEQ */
0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D,
0x01, 0x07, 0x01, /* OID pkcs7-data */
0xA0, 0x11, /* [0] CONSTRUCTED ctx */
0x04, 0x0F, /* OCTET STRING */
0x30, 0x0D, /* SEQ of ContentInfo arr */
0x30, 0x05, /* ContentInfo SEQ, length=5 LIE */
0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D,
0x01, 0x07, 0x01 /* OID: 11 bytes actual */
};

ExpectNotNull(pkcs12 = wc_PKCS12_new());
ExpectIntEQ(wc_d2i_PKCS12(crafted, (word32)sizeof(crafted), pkcs12),
ASN_PARSE_E);
wc_PKCS12_free(pkcs12);
#endif
return EXPECT_RESULT();
}

6 changes: 4 additions & 2 deletions tests/api/test_pkcs12.h
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Expand Up @@ -27,10 +27,12 @@
int test_wc_i2d_PKCS12(void);
int test_wc_PKCS12_create(void);
int test_wc_d2i_PKCS12_bad_mac_salt(void);
int test_wc_d2i_PKCS12_oid_underflow(void);

#define TEST_PKCS12_DECLS \
TEST_DECL_GROUP("pkcs12", test_wc_i2d_PKCS12), \
TEST_DECL_GROUP("pkcs12", test_wc_PKCS12_create), \
TEST_DECL_GROUP("pkcs12", test_wc_d2i_PKCS12_bad_mac_salt)
TEST_DECL_GROUP("pkcs12", test_wc_PKCS12_create), \
TEST_DECL_GROUP("pkcs12", test_wc_d2i_PKCS12_bad_mac_salt), \
TEST_DECL_GROUP("pkcs12", test_wc_d2i_PKCS12_oid_underflow)

#endif /* WOLFCRYPT_TEST_PKCS12_H */
6 changes: 6 additions & 0 deletions wolfcrypt/src/pkcs12.c
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Original file line number Diff line number Diff line change
Expand Up @@ -334,6 +334,12 @@ static int GetSafeContent(WC_PKCS12* pkcs12, const byte* input,
return ret;
}

/* Check that OID did not consume more than the sequence length */
if (localIdx > curIdx + (word32)curSz) {
freeSafe(safe, pkcs12->heap);
return ASN_PARSE_E;
}

/* create new content info struct ... possible OID sanity check? */
ci = (ContentInfo*)XMALLOC(sizeof(ContentInfo), pkcs12->heap,
DYNAMIC_TYPE_PKCS);
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