commit 1c28a36116110db5de40e6edf09887651f3ca37b
from: Omar Polo <op@omarpolo.com>
date: Tue Oct 25 07:37:58 2022 UTC

check size before calling mmap(2)

It's only a preparatory step, as checking whether a size_t is less than
SIZE_MAX is moot.  In a follow-up commit, however, the `filesize' field
of the struct got_pack will become off_t and these checks will kick in.
This also makes consistent how we guard mmap(2) against empty files.

ok and improvements stsp@

commit - 5326bd73c63d9b453093bf46a5a514283348d0ec
commit + 1c28a36116110db5de40e6edf09887651f3ca37b
blob - f8e685448165384cfc578c0f089b4aa6fb6219c8
blob + 7bc7eb3dcdcec57157f35f8b6c676e1979ba2b76
--- lib/object.c
+++ lib/object.c
@@ -926,7 +926,10 @@ got_object_raw_alloc(struct got_raw_object **obj, uint
     size_t hdrlen, off_t size)
 {
 	const struct got_error *err = NULL;
+	off_t tot;
 
+	tot = hdrlen + size;
+
 	*obj = calloc(1, sizeof(**obj));
 	if (*obj == NULL) {
 		err = got_error_from_errno("calloc");
@@ -944,13 +947,13 @@ got_object_raw_alloc(struct got_raw_object **obj, uint
 			goto done;
 		}
 
-		if (sb.st_size != hdrlen + size) {
+		if (sb.st_size != tot) {
 			err = got_error(GOT_ERR_PRIVSEP_LEN);
 			goto done;
 		}
 #ifndef GOT_PACK_NO_MMAP
-		if (hdrlen + size > 0) {
-			(*obj)->data = mmap(NULL, hdrlen + size, PROT_READ,
+		if (tot > 0 && tot <= SIZE_MAX) {
+			(*obj)->data = mmap(NULL, tot, PROT_READ,
 			    MAP_PRIVATE, *outfd, 0);
 			if ((*obj)->data == MAP_FAILED) {
 				if (errno != ENOMEM) {
blob - fd881a7c9ce48fda7e1c9997d71b47a93bba6268
blob + b043d4d76bcee830e606273e62636fe996c1d756
--- lib/pack.c
+++ lib/pack.c
@@ -392,13 +392,15 @@ got_packidx_open(struct got_packidx **packidx,
 	}
 
 #ifndef GOT_PACK_NO_MMAP
-	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
-	if (p->map == MAP_FAILED) {
-		if (errno != ENOMEM) {
-			err = got_error_from_errno("mmap");
-			goto done;
+	if (p->len > 0 && p->len <= SIZE_MAX) {
+		p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
+		if (p->map == MAP_FAILED) {
+			if (errno != ENOMEM) {
+				err = got_error_from_errno("mmap");
+				goto done;
+			}
+			p->map = NULL; /* fall back to read(2) */
 		}
-		p->map = NULL; /* fall back to read(2) */
 	}
 #endif
 
@@ -1036,7 +1038,6 @@ static const struct got_error *
 resolve_offset_delta(struct got_delta_chain *deltas,
     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
-
 {
 	const struct got_error *err;
 	off_t base_offset;
blob - b07bf0c9c711997031a7d3afa3388a27527ef2db
blob + 50237bbf7e4f90efc06e68c84cedd6c84631551e
--- lib/repository.c
+++ lib/repository.c
@@ -1428,14 +1428,16 @@ got_repo_cache_pack(struct got_pack **packp, struct go
 		goto done;
 
 #ifndef GOT_PACK_NO_MMAP
-	pack->map = mmap(NULL, pack->filesize, PROT_READ, MAP_PRIVATE,
-	    pack->fd, 0);
-	if (pack->map == MAP_FAILED) {
-		if (errno != ENOMEM) {
-			err = got_error_from_errno("mmap");
-			goto done;
+	if (pack->filesize > 0 && pack->filesize <= SIZE_MAX) {
+		pack->map = mmap(NULL, pack->filesize, PROT_READ, MAP_PRIVATE,
+		    pack->fd, 0);
+		if (pack->map == MAP_FAILED) {
+			if (errno != ENOMEM) {
+				err = got_error_from_errno("mmap");
+				goto done;
+			}
+			pack->map = NULL; /* fall back to read(2) */
 		}
-		pack->map = NULL; /* fall back to read(2) */
 	}
 #endif
 done:
blob - 8a38382357c6aeb5b642965a26a50d9a6621d34e
blob + 7fda0c4e47f3539c4b13427d388cc26e749b75bb
--- libexec/got-index-pack/got-index-pack.c
+++ libexec/got-index-pack/got-index-pack.c
@@ -183,10 +183,12 @@ main(int argc, char **argv)
 	}
 
 #ifndef GOT_PACK_NO_MMAP
-	pack.map = mmap(NULL, pack.filesize, PROT_READ, MAP_PRIVATE,
-	    pack.fd, 0);
-	if (pack.map == MAP_FAILED)
-		pack.map = NULL; /* fall back to read(2) */
+	if (pack.filesize > 0 && pack.filesize <= SIZE_MAX) {
+		pack.map = mmap(NULL, pack.filesize, PROT_READ, MAP_PRIVATE,
+		    pack.fd, 0);
+		if (pack.map == MAP_FAILED)
+			pack.map = NULL; /* fall back to read(2) */
+	}
 #endif
 	err = got_pack_index(&pack, idxfd, tmpfiles[0], tmpfiles[1],
 	    tmpfiles[2], pack_hash, send_index_pack_progress, &ibuf, &rl);
blob - 268ab18c5371e622b7f9c3a62c9a894a7050de85
blob + e49fd95ba0b7919efe9005b306782db008b22370
--- libexec/got-read-pack/got-read-pack.c
+++ libexec/got-read-pack/got-read-pack.c
@@ -1146,9 +1146,11 @@ receive_packidx(struct got_packidx **packidx, struct i
 	}
 
 #ifndef GOT_PACK_NO_MMAP
-	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
-	if (p->map == MAP_FAILED)
-		p->map = NULL; /* fall back to read(2) */
+	if (p->len > 0 && p->len <= SIZE_MAX) {
+		p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
+		if (p->map == MAP_FAILED)
+			p->map = NULL; /* fall back to read(2) */
+	}
 #endif
 	err = got_packidx_init_hdr(p, 1, ipackidx.packfile_size);
 done:
@@ -1874,10 +1876,12 @@ receive_pack(struct got_pack **packp, struct imsgbuf *
 		goto done;
 
 #ifndef GOT_PACK_NO_MMAP
-	pack->map = mmap(NULL, pack->filesize, PROT_READ, MAP_PRIVATE,
-	    pack->fd, 0);
-	if (pack->map == MAP_FAILED)
-		pack->map = NULL; /* fall back to read(2) */
+	if (pack->filesize > 0 && pack->filesize <= SIZE_MAX) {
+		pack->map = mmap(NULL, pack->filesize, PROT_READ, MAP_PRIVATE,
+		    pack->fd, 0);
+		if (pack->map == MAP_FAILED)
+			pack->map = NULL; /* fall back to read(2) */
+	}
 #endif
 done:
 	if (err) {