* [PATCH 0/2] xap_helper C++ fixes
@ 2023-11-27 21:54 7% Eric Wong
2023-11-27 21:54 6% ` [PATCH 2/2] xap_helper.h: avoid some off_t vs size_t problems Eric Wong
0 siblings, 1 reply; 2+ results
From: Eric Wong @ 2023-11-27 21:54 UTC (permalink / raw)
To: meta
Already pushed out since I forgot which VM I was on :x
Eric Wong (2):
xap_helper: avoid strerror(3) inside signal handler
xap_helper.h: avoid some off_t vs size_t problems
lib/PublicInbox/xap_helper.h | 59 ++++++++++++++++++------------------
1 file changed, 30 insertions(+), 29 deletions(-)
^ permalink raw reply [relevance 7%]
* [PATCH 2/2] xap_helper.h: avoid some off_t vs size_t problems
2023-11-27 21:54 7% [PATCH 0/2] xap_helper C++ fixes Eric Wong
@ 2023-11-27 21:54 6% ` Eric Wong
0 siblings, 0 replies; 2+ results
From: Eric Wong @ 2023-11-27 21:54 UTC (permalink / raw)
To: meta
We'll introduce a helper to cast off_t to size_t consistently
for mmap/munmap/calloc calls which require size_t. Also, an
extra check for multiplication overflow can be helpful just
in case we end up with a gigantic file roots file.
---
lib/PublicInbox/xap_helper.h | 30 ++++++++++++++++++------------
1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/lib/PublicInbox/xap_helper.h b/lib/PublicInbox/xap_helper.h
index 1d8437c9..5816c24c 100644
--- a/lib/PublicInbox/xap_helper.h
+++ b/lib/PublicInbox/xap_helper.h
@@ -360,6 +360,13 @@ static void xclose(int fd)
EABORT("BUG: close");
}
+static size_t off2size(off_t n)
+{
+ if (n < 0 || (uintmax_t)n > SIZE_MAX)
+ ABORT("off_t out of size_t range: %lld\n", (long long)n);
+ return (size_t)n;
+}
+
#define CLEANUP_DUMP_ROOTS __attribute__((__cleanup__(dump_roots_ensure)))
static void dump_roots_ensure(void *ptr)
{
@@ -367,8 +374,9 @@ static void dump_roots_ensure(void *ptr)
if (drt->root2off_fd >= 0)
xclose(drt->root2off_fd);
hdestroy(); // idempotent
- if (drt->mm_ptr && munmap(drt->mm_ptr, drt->sb.st_size))
- EABORT("BUG: munmap(%p, %zu)", drt->mm_ptr, drt->sb.st_size);
+ size_t size = off2size(drt->sb.st_size);
+ if (drt->mm_ptr && munmap(drt->mm_ptr, size))
+ EABORT("BUG: munmap(%p, %zu)", drt->mm_ptr, size);
free(drt->entries);
fbuf_ensure(&drt->wbuf);
}
@@ -516,20 +524,18 @@ static bool cmd_dump_roots(struct req *req)
// each entry is at least 43 bytes ({OIDHEX}\0{INT}\0),
// so /32 overestimates the number of expected entries by
// ~%25 (as recommended by Linux hcreate(3) manpage)
- size_t est = (drt.sb.st_size / 32) + 1; //+1 for "\0" termination
- if ((uint64_t)drt.sb.st_size > (uint64_t)SIZE_MAX)
- err(EXIT_FAILURE, "%s size too big (%lld bytes > %zu)",
- root2off_file, (long long)drt.sb.st_size, SIZE_MAX);
- drt.mm_ptr = mmap(NULL, drt.sb.st_size, PROT_READ,
+ size_t size = off2size(drt.sb.st_size);
+ size_t est = (size / 32) + 1; //+1 for "\0" termination
+ drt.mm_ptr = mmap(NULL, size, PROT_READ,
MAP_PRIVATE, drt.root2off_fd, 0);
if (drt.mm_ptr == MAP_FAILED)
- err(EXIT_FAILURE, "mmap(%zu, %s)",
- drt.sb.st_size, root2off_file);
- drt.entries = (char **)calloc(est * 2, sizeof(char *));
+ err(EXIT_FAILURE, "mmap(%zu, %s)", size, root2off_file);
+ size_t asize = est * 2;
+ if (asize < est) ABORT("too many entries: %zu", est);
+ drt.entries = (char **)calloc(asize, sizeof(char *));
if (!drt.entries)
err(EXIT_FAILURE, "calloc(%zu * 2, %zu)", est, sizeof(char *));
- size_t tot = split2argv(drt.entries, (char *)drt.mm_ptr,
- drt.sb.st_size, est * 2);
+ size_t tot = split2argv(drt.entries, (char *)drt.mm_ptr, size, asize);
if (tot <= 0) return false; // split2argv already warned on error
if (!hcreate(est))
err(EXIT_FAILURE, "hcreate(%zu)", est);
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