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lws_b64_decode_stateful truncates response #2855

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darhaywa opened this issue Mar 23, 2023 · 0 comments
Open

lws_b64_decode_stateful truncates response #2855

darhaywa opened this issue Mar 23, 2023 · 0 comments

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@darhaywa
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Accurately sized output buffers have truncated decodes.

Given the following base64 encoded string of 1708 characters, which decodes to 1279 bytes on https://cryptii.com/pipes/base64-to-binary, when passed through lws_b64_decode_string_len(inputString, 1708, outputBuffer, 1281) only 1278 bytes are returned. This continues until the output buffer size of 1283 is provided.

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
darhaywa added a commit to darhaywa/libwebsockets that referenced this issue Mar 23, 2023
@darhaywa
lws_b64_decode_stateful truncates response
70d41ec 
Addresses issue warmcat#2855 by allowing the parsing of the final byte when there are at least 3 bytes remaining in the buffer.

For every 4 bytes of input, a maximum of 3 bytes of output are generated when decoding the base64 string. The buffer space, therefore, only requires an additional 3 bytes of space. The code checks for space in the buffer before adding null termination.
@darhaywa darhaywa mentioned this issue Mar 23, 2023
Closed
lws-team pushed a commit that referenced this issue Nov 13, 2023
@darhaywa @lws-team
b64: lws_b64_decode_stateful truncates response
0586d01 
Addresses issue #2855 by allowing the parsing of the final byte when there are at least 3 bytes remaining in the buffer.

For every 4 bytes of input, a maximum of 3 bytes of output are generated when decoding the base64 string. The buffer space, therefore, only requires an additional 3 bytes of space. The code checks for space in the buffer before adding null termination.
lws-team pushed a commit that referenced this issue Nov 13, 2023
@darhaywa @lws-team
b64: lws_b64_decode_stateful truncates response
ac9e3ba 
Addresses issue #2855 by allowing the parsing of the final byte when there are at least 3 bytes remaining in the buffer.

For every 4 bytes of input, a maximum of 3 bytes of output are generated when decoding the base64 string. The buffer space, therefore, only requires an additional 3 bytes of space. The code checks for space in the buffer before adding null termination.
lws-team pushed a commit that referenced this issue Nov 24, 2023
@darhaywa @lws-team
b64: lws_b64_decode_stateful truncates response
22621f3 
Addresses issue #2855 by allowing the parsing of the final byte when there are at least 3 bytes remaining in the buffer.

For every 4 bytes of input, a maximum of 3 bytes of output are generated when decoding the base64 string. The buffer space, therefore, only requires an additional 3 bytes of space. The code checks for space in the buffer before adding null termination.
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