Reject malformed input in mg_json_get_hex#3634
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scaprile
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You need to sign the CLA if you want this to be merged, otherwise we will close this PR and may do something different that serves the same purpose.
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| if (!mg_str_to_num(mg_str_n(json.buf + off + 1 + i, 2), 16, | ||
| &result[i >> 1], sizeof(uint8_t))) { | ||
| mg_free(result); | ||
| return NULL; | ||
| } |
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I don't like this style, it shifts the attention from the algorithm to handling wreckage. I would break on a single line and check/free after the loop, also on a single line
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Please do not add those long, ugly, and useless AI-generated commit comments; and please let me know when you signed the CLA. |
scaprile
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July 14, 2026 20:40
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Jul 14, 2026
Reject odd-length and non-hex strings before decoding them. Tested: 1796 ASan/UBSan tests in amalgamated and unamalgamated builds
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I have signed the Cesanta CLA. I also squashed the branch to one commit and shortened the commit message as requested. |
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@cpq WDYT ? LGTM |
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mg_json_get_hex()currently ignores failedmg_str_to_num()calls and processes odd-length strings in two-character steps. As a result,0gsucceeds as byte0x00, andabcsucceeds as byte0xabinstead of reporting invalid input.Reject odd-length and non-hex strings while preserving valid input and the existing empty-string behavior. The unit tests now cover empty, odd-length, and non-hex inputs.
Testing:
make -B -C test test TFLAGS=-DLOCALHOST_ONLY(ASan/UBSan, 1796 tests)make -B -C test unamalgamated TFLAGS=-DLOCALHOST_ONLY, thenunit_test(ASan/UBSan, 1796 tests)mongoose.candmongoose.hwith the repository Makefile; no diff