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util/nvmutil: Only allocate needed memory for file 

We were allocating 128KB even if we only needed 8KB, for
example. It's not a lot of memory, but the principle of
the matter is that we must respect the user by not wasting
their memory.

The design of nvmutil is that it will never overflow, because
operations are mapped in memory to the exact size of the gbe
file, which can be 8KB, 16KB or 128KB, and this is enforced.

Signed-off-by: Leah Rowe <leah@libreboot.org>
master
Leah Rowe 2025-01-26 06:00:49 +00:00
parent ed45da9cae
commit cdf23975bc
1 changed files with 7 additions and 2 deletions
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9
util/nvmutil/nvmutil.c
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@ -31,7 +31,7 @@ uint8_t hextonum(char chs), rhex(void);
#define SIZE_64KB 0x10000
#define SIZE_128KB 0x20000
uint16_t buf16[SIZE_64KB], mac[3] = {0, 0, 0};
uint16_t mac[3] = {0, 0, 0}, *buf16;
size_t partsize, nf, gbe[2];
uint8_t nvmPartChanged[2] = {0, 0}, skipread[2] = {0, 0};
int e = 1, flags, rfd, fd, part, gbeFileChanged = 0;
@ -198,6 +198,10 @@ openFiles(const char *path)
void
readGbe(void)
{
char *buf = malloc(partsize << 1);
if (buf == NULL)
err(errno, "Can't malloc %ld B for '%s'", partsize, filename);
if ((cmd == writeGbe) || (cmd == cmd_copy))
nf = partsize; /* read/write the entire block */
else
@ -207,8 +211,9 @@ readGbe(void)
skipread[part ^ 1] = 1; /* only read the user-specified part */
/* we pread per-part, so each part has its own pointer: */
gbe[0] = (size_t) buf16;
gbe[0] = (size_t) buf;
gbe[1] = gbe[0] + partsize;
buf16 = (uint16_t *) buf;
for (int p = 0; p < 2; p++) {
if (skipread[p])