mirrors/tar
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Fix xsparse.c big heap allocation bugs

Browse Source 
* scripts/xsparse.c (expand_sparse): Read into auto buffer, not heap.
The heap code was wrong for two reasons: it called malloc just once
in the try-again loop, and even when it succeeded it could have
left so few bytes available in the heap that later stdio calls
could fail.  Reading into the auto buffer might be a bit slower
but speed is not an issue here and it’s better to be simple.
This commit is contained in:
Paul Eggert
2024-11-06 10:02:02 -08:00
parent a855a80d06
commit ac06d4d104
1 changed files with 2 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
scripts/xsparse.c
View File

@@ -281,19 +281,6 @@ static void
expand_sparse (FILE *sfp, int ofd)
{
size_t i;
off_t max_numbytes = 0;
size_t maxbytes;
char *buffer;
for (i = 0; i < sparse_map_size; i++)
if (max_numbytes < sparse_map[i].numbytes)
max_numbytes = sparse_map[i].numbytes;
maxbytes = max_numbytes < SIZE_MAX ? max_numbytes : SIZE_MAX;
for (buffer = malloc (maxbytes); !buffer; maxbytes /= 2)
if (maxbytes == 0)
die (1, "not enough memory");
for (i = 0; i < sparse_map_size; i++)
{
@@ -310,7 +297,8 @@ expand_sparse (FILE *sfp, int ofd)
die (1, "lseek error (%d)", errno);
while (size)
{
size_t rdsize = (size < maxbytes) ? size : maxbytes;
char buffer[BUFSIZ];
size_t rdsize = size < BUFSIZ ? size : BUFSIZ;
if (rdsize != fread (buffer, 1, rdsize, sfp))
die (1, "read error (%d)", errno);
if (0 <= ofd)
@@ -323,7 +311,6 @@ expand_sparse (FILE *sfp, int ofd)
}
}
}
free (buffer);
}
static void