nss: only cache valid CRL entries #4053
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lib/vtls/nss.c
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| /* unable to cache CRL */ | ||
| /* store the CRL item so that we can free it in Curl_nss_cleanup() */ | ||
| if(insert_wrapped_ptr(&nss_crl_list, crl_der) != CURLE_OK) { | ||
| SECITEM_FreeItem(crl_der, PR_TRUE); |
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You need to call CERT_UncacheCRL() before releasing the memory to avoid a possible use after free later on. If CERT_UncacheCRL() fails, which is unlikely, it is IMO better to leak the memory. Something like:
if(SECSuccess == CERT_UncacheCRL(db, crl_der))
SECITEM_FreeItem(crl_der, PR_TRUE);
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Ah, nice catch, fixed and rebased.
Change the logic around such that we only keep CRLs that NSS actually ended up caching around for later deletion. If CERT_CacheCRL() fails then there is little point in delaying the freeing of the CRL as it is not used. Closes #xxxx
danielgustafsson
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A thing to note which I failed to write in the commitmessage (but will amend before pushing if approved) is that without this we leave a dangling pointer on |
I do not understand the above note. Are you talking about the original implementation? It did not (immediately) call |
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On 20 Jun 2019, at 15:16, Kamil Dudka ***@***.***> wrote:
I do not understand the above note. Are you talking about the original implementation? It did not (immediately) call SECITEM_FreeItem() upon failure of CERT_CacheCRL(). The only problem was that the memory was released too late as I understand it.
Sorry, I managed to confuse myself reading the code - the original implementation did indeed not have such a bug. I clearly need more coffee today..
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No problem, thank you for clarifying it! And thank you for improving the code! |
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Thanks |
Change the logic around such that we only keep CRLs that NSS actually ended up caching around for later deletion. If CERT_CacheCRL() fails then there is little point in delaying the freeing of the CRL as it is not used.