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Hardening: Fix memory leak in pcapng fail path and secure realloc logic #1665

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Hardening: Fix memory leak in pcapng fail path and secure realloc logic #1665

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9 changes: 3 additions & 6 deletions sf-pcapng.c
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Original file line number Diff line number Diff line change
Expand Up @@ -343,6 +343,7 @@ read_block(FILE *fp, pcap_t *p, struct block_cursor *cursor, char *errbuf)
return (-1);
}
p->buffer = bigger_buffer;
p->bufsize = bhdr.total_length;
}

/*
Expand Down Expand Up @@ -902,9 +903,7 @@ pcap_ng_check_header(const uint8_t *magic, FILE *fp, u_int precision,
default:
snprintf(errbuf, PCAP_ERRBUF_SIZE,
"unknown time stamp resolution %u", precision);
free(p);
*err = 1;
return (NULL);
goto fail;
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@guyharris guyharris Mar 30, 2026

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Not sure there's a leak there, as nothing other than the pcap_t-plus-private-data was allocated, and it's freed, but this is good practice anyway in case the code changes - the resource deallocation is, at least, centralized.

(This is not one of C's strengths.)

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@Noamismach Noamismach Mar 30, 2026

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Agreed. Even if the secondary allocations havent occurred yet at this specific point, funneling everything through a centralized goto fail block removes a major footgun for future modifications. And yes, definitely not one of C's strengths!

}

p->opt.tstamp_precision = precision;
Expand All @@ -931,9 +930,7 @@ pcap_ng_check_header(const uint8_t *magic, FILE *fp, u_int precision,
p->buffer = malloc(p->bufsize);
if (p->buffer == NULL) {
snprintf(errbuf, PCAP_ERRBUF_SIZE, "out of memory");
free(p);
*err = 1;
return (NULL);
goto fail;
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@guyharris guyharris Mar 30, 2026

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Ditto.

}
ps->max_blocksize = INITIAL_MAX_BLOCKSIZE;

Expand Down