The analysis is based on the provided commit ca1672134b3e2962cd392212c73f44f8f4cb489f, which is stated to be the patch for the described vulnerability. The commit message itself, 'src/conv.c, src/io-sim.c, src/search.c: Avoid integer overflow leading to heap overflow', indicates the nature and location of the fixes.

The vulnerability description mentions that the function vbi_strndup_iconv_ucs2 in src/conv.c is affected by an integer overflow due to manipulation of src_length. While vbi_strndup_iconv_ucs2 is not explicitly shown as modified in the provided diff, the function strndup_utf8_ucs2 in the same file (src/conv.c) is patched to fix an integer overflow related to a src_length parameter during memory allocation (src_length * 3 + 1). This is a strong indication that strndup_utf8_ucs2 is either the function referred to in the description, a function called by vbi_strndup_iconv_ucs2, or that vbi_strndup_iconv_ucs2 had a similar pattern fixed which might not be fully detailed in the snippet but is covered by the commit's scope.

The other functions listed (strndup_identity in src/conv.c, vbi_capture_sim_load_caption in src/io-sim.c, and vbi_search_new in src/search.c) were also modified in the same commit to prevent similar integer overflows in memory allocation size calculations. Therefore, these functions, in their state prior to the patch, also contained vulnerabilities of the same type (integer overflow leading to potential heap overflow).

The identified functions are those where the patch explicitly introduced checks to prevent integer overflows during buffer size calculations for memory allocation. The 'patch_evidence' points to the vulnerable code pattern (the unchecked calculation) that existed before the fix.