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Clam 2211 Add string length validation to public key strings #810

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Merged
val-ms merged 1 commit into from
Feb 2, 2023
Merged

Clam 2211 Add string length validation to public key strings #810

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19 changes: 14 additions & 5 deletions libclamav/readdb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1206,11 +1206,11 @@ static int cli_chkpua(const char *signame, const char *pua_cats, unsigned int op
cli_dbgmsg("Skipping signature %s - bad syntax\n", signame);
return 1;
}
if ( (pt2 = strrchr(sig + 1, '.')) != pt1 ) {
if ((pt2 = strrchr(sig + 1, '.')) != pt1) {
cli_dbgmsg("Signature has at least three dots [%s]\n", signame);
}
if ((unsigned int)(pt1 - sig + 2) > sizeof(cat)) {
cli_dbgmsg("Skipping signature %s - too long category name, length approaching %d characters\n", signame, (unsigned int)(pt1 - sig + 2) );
cli_dbgmsg("Skipping signature %s - too long category name, length approaching %d characters\n", signame, (unsigned int)(pt1 - sig + 2));
return 1;
}
if ((unsigned int)(pt2 - sig + 2) > sizeof(cat)) {
Expand All @@ -1221,9 +1221,9 @@ static int cli_chkpua(const char *signame, const char *pua_cats, unsigned int op
endsig = strrchr(sig, '.');
strncpy(cat, sig, strlen(sig) - strlen(endsig) + 1);
cat[strlen(sig) - strlen(endsig) + 1] = 0;
cat_pt = strstr(cat, pua_cats);
cli_dbgmsg("cli_chkpua: cat=[%s]\n", cat );
cli_dbgmsg("cli_chkpua: sig=[%s]\n", sig );
cat_pt = strstr(cat, pua_cats);
cli_dbgmsg("cli_chkpua: cat=[%s]\n", cat);
cli_dbgmsg("cli_chkpua: sig=[%s]\n", sig);
if (options & CL_DB_PUA_INCLUDE)
ret = cat_pt ? 0 : 1;
else
Expand Down Expand Up @@ -3418,6 +3418,15 @@ static int cli_loadcrt(FILE *fs, struct cl_engine *engine, struct cli_dbio *dbio
goto done;
}

/*
* tokens[4] is the public key. having a length that is too
* long causes an out of bounds read in the this call.
*/
if ((strlen(tokens[4]) / 2) >= (FP_MAX_SIZE / 8)) {
cli_errmsg("cli_loadcrt: line %u: Public key too long.\nNOTE: If this is actually a valid key length, recompile with a larger FP_MAX_SIZE (currently %d).\n", (unsigned int)line, FP_MAX_SIZE);
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@val-ms val-ms Jan 31, 2023

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I like the note. Nice.

ret = CL_EMALFDB;
goto done;
}
fp_read_unsigned_bin(&(ca.n), (const unsigned char *)pubkey, strlen(tokens[4]) / 2);

fp_read_unsigned_bin(&(ca.e), exp, sizeof(exp) - 1);
Expand Down