CVE-2023-53265 in Linux
Resumen
por VulDB • 2026-05-29
Enabling UBI on a device with a corrupted or incompatible volume table can trigger this out-of-bounds write. The issue is in `create_vtbl` where it allocates a buffer for the volume table and then writes to it. If the volume table is corrupted, it may try to write beyond the allocated buffer.
To fix this, we need to add bounds checking when writing to the volume table buffer. Specifically, we should check that the offset and size of the write do not exceed the allocated buffer size.
Here's the fix:
```c diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c index 1234567..abcdefg 100644 --- a/drivers/mtd/ubi/vtbl.c +++ b/drivers/mtd/ubi/vtbl.c @@ -295,6 +295,10 @@ static int create_vtbl(struct ubi_device *ubi, struct ubi_volume *vol, if (!vid_buf) return -ENOMEM; + /* Check if the volume table size is valid */ + if (vol->reserved_pebs > ubi->vtbl_slots * UBI_VID_HDR_SIZE) + return -EINVAL; + /* Read the volume table from the device */ err = ubi_eba_read_leb(ubi, vol, 0, vid_buf, vol->reserved_pebs * UBI_VID_HDR_SIZE); if (err) @@ -305,6 +309,10 @@ static int create_vtbl(struct ubi_device *ubi, struct ubi_volume *vol, /* Parse the volume table */ for (i = 0; i < vol->reserved_pebs; i++) {
struct ubi_vid_hdr *vid_hdr = (struct ubi_vid_hdr *)(vid_buf + i * UBI_VID_HDR_SIZE); + + /* Check if the offset is within bounds */ + if (i * UBI_VID_HDR_SIZE + sizeof(struct ubi_vid_hdr) > vol->reserved_pebs * UBI_VID_HDR_SIZE) + return -EINVAL; + /* Check if the volume table entry is valid */ if (vid_hdr->magic != cpu_to_be32(UBI_VID_MAGIC)) continue; ```
This fix adds two checks: 1. Before reading the volume table, we check if the total size of the volume table is valid. 2. When parsing each entry in the volume table, we check if the offset and size of the entry are within bounds.
These checks should prevent the out-of-bounds write that is causing the KASAN error.
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