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LibCrypto: Remove all uses of VLAs

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This removes all uses of VLAs with either Vectors with inline capacity
for the expected soft upper bound, or the occasional heap allocation.
This commit is contained in:
Ali Mohammad Pur 2021-05-13 12:13:11 +04:30 • committed by Andreas Kling
parent 0d50d3ed1e
commit b05beb79d4
7 changed files with 41 additions and 36 deletions
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22
Userland/Libraries/LibCrypto/PK/RSA.cpp
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@ -293,8 +293,9 @@ void RSA_EMSA_PSS<HashFunction>::sign(ReadonlyBytes in, Bytes& out)
// -- encode via EMSA_PSS
auto mod_bits = m_rsa.private_key().modulus().trimmed_length() * sizeof(u32) * 8;
u8 EM[mod_bits];
auto EM_buf = Bytes { EM, mod_bits };
Vector<u8, 2048> EM;
EM.resize(mod_bits);
auto EM_buf = Bytes { EM };
m_emsa_pss.encode(in, EM_buf, mod_bits - 1);
// -- sign via RSA
@ -308,8 +309,9 @@ VerificationConsistency RSA_EMSA_PSS<HashFunction>::verify(ReadonlyBytes in)
if (in.size() != mod_bytes)
return VerificationConsistency::Inconsistent;
u8 EM[mod_bytes];
auto EM_buf = Bytes { EM, mod_bytes };
Vector<u8, 256> EM;
EM.resize(mod_bytes);
auto EM_buf = Bytes { EM };
// -- verify via RSA
m_rsa.verify(in, EM_buf);
@ -333,22 +335,20 @@ void RSA_PKCS1_EME::encrypt(ReadonlyBytes in, Bytes& out)
}
auto ps_length = mod_len - in.size() - 3;
u8 ps[ps_length];
Vector<u8, 8096> ps;
ps.resize(ps_length);
// FIXME: Without this assertion, GCC refuses to compile due to a memcpy overflow(!?)
VERIFY(ps_length < 16384);
fill_with_random(ps, ps_length);
fill_with_random(ps.data(), ps_length);
// since arc4random can create zeros (shocking!)
// we have to go through and un-zero the zeros
for (size_t i = 0; i < ps_length; ++i)
while (!ps[i])
fill_with_random(ps + i, 1);
fill_with_random(ps.span().offset(i), 1);
u8 paddings[] { 0x00, 0x02 };
out.overwrite(0, paddings, 2);
out.overwrite(2, ps, ps_length);
out.overwrite(2, ps.data(), ps_length);
out.overwrite(2 + ps_length, paddings, 1);
out.overwrite(3 + ps_length, in.data(), in.size());
out = out.trim(3 + ps_length + in.size()); // should be a single block