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net-lwip: tftp: add LMB and buffer checks

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Legacy NET tftp invokes a store_block() function which performs buffer
validation (LMB, address wrapping). Do the same with NET_LWIP.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Suggested-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Acked-by: Sughosh Ganu <sughosh.ganu@linaro.org>
Tested-by: Sughosh Ganu <sughosh.ganu@linaro.org>
This commit is contained in:
Jerome Forissier
2025-04-17 15:27:00 +02:00
parent e40c910e88
commit 1bc91fa98c
1 changed files with 45 additions and 11 deletions
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56
net/lwip/tftp.c
View File

@@ -8,6 +8,7 @@
#include <efi_loader.h> #include <efi_loader.h>
#include <image.h> #include <image.h>
#include <linux/delay.h> #include <linux/delay.h>
#include <linux/kconfig.h>
#include <lwip/apps/tftp_client.h> #include <lwip/apps/tftp_client.h>
#include <lwip/timeouts.h> #include <lwip/timeouts.h>
#include <mapmem.h> #include <mapmem.h>
@@ -31,6 +32,47 @@ struct tftp_ctx {
enum done_state done; enum done_state done;
}; };
/**
* store_block() - copy received data
*
* This function is called by the receive callback to copy a block of data
* into its final location (ctx->daddr). Before doing so, it checks if the copy
* is allowed.
*
* @ctx: the context for the current transfer
* @src: the data received from the TCP stack
* @len: the length of the data
*/
static int store_block(struct tftp_ctx *ctx, void *src, u16_t len)
{
ulong store_addr = ctx->daddr;
void *ptr;
if (CONFIG_IS_ENABLED(LMB)) {
if (store_addr + len < store_addr ||
lmb_read_check(store_addr, len)) {
puts("\nTFTP error: ");
puts("trying to overwrite reserved memory...\n");
return -1;
}
}
ptr = map_sysmem(store_addr, len);
memcpy(ptr, src, len);
unmap_sysmem(ptr);
ctx->daddr += len;
ctx->size += len;
ctx->block_count++;
if (ctx->block_count % 10 == 0) {
putc('#');
if (ctx->block_count % (65 * 10) == 0)
puts("\n\t ");
}
return 0;
}
static void *tftp_open(const char *fname, const char *mode, u8_t is_write) static void *tftp_open(const char *fname, const char *mode, u8_t is_write)
{ {
return NULL; return NULL;
@@ -71,17 +113,9 @@ static int tftp_write(void *handle, struct pbuf *p)
struct tftp_ctx *ctx = handle; struct tftp_ctx *ctx = handle;
struct pbuf *q; struct pbuf *q;
for (q = p; q; q = q->next) { for (q = p; q; q = q->next)
memcpy((void *)ctx->daddr, q->payload, q->len); if (store_block(ctx, q->payload, q->len) < 0)
ctx->daddr += q->len; return -1;
ctx->size += q->len;
ctx->block_count++;
if (ctx->block_count % 10 == 0) {
putc('#');
if (ctx->block_count % (65 * 10) == 0)
puts("\n\t ");
}
}
return 0; return 0;
} }