CVE-2021-47383
In the Linux kernel, the following vulnerability has been resolved: tty: Fix out-of-bound vmalloc access in imageblit This issue happens when a userspace program does an ioctl FBIOPUT_VSCREENINFO passing the fb_var_screeninfo struct containing only the…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.27%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: tty: Fix out-of-bound vmalloc access in imageblit This issue happens when a userspace program does an ioctl FBIOPUT_VSCREENINFO passing the fb_var_screeninfo struct containing only the fields xres, yres, and bits_per_pixel with values. If this struct is the same as the previous ioctl, the vc_resize() detects it and doesn't call the resize_screen(), leaving the fb_var_screeninfo incomplete. And this leads to the updatescrollmode() calculates a wrong value to fbcon_display->vrows, which makes the real_y() return a wrong value of y, and that value, eventually, causes the imageblit to access an out-of-bound address value. To solve this issue I made the resize_screen() be called even if the screen does not need any resizing, so it will "fix and fill" the fb_var_screeninfo independently.
- CVSS 3.1
- 7.1 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- EPSS
- 0.27% probability · 18th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-125
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/067c694d06040db6f0c65281bb358452ca6d85b9Patch
- https://git.kernel.org/stable/c/3b0c406124719b625b1aba431659f5cdc24a982cPatch
- https://git.kernel.org/stable/c/699d926585daa6ec44be556cdc1ab89e5d54557bPatch
- https://git.kernel.org/stable/c/70aed03b1d5a5df974f456cdc8eedb213c94bb8bPatch
- https://git.kernel.org/stable/c/7e71fcedfda6f7de18f850a6b36e78d78b04476fPatch
- https://git.kernel.org/stable/c/883f7897a25e3ce14a7f274ca4c73f49ac84002aPatch
- https://git.kernel.org/stable/c/8a6a240f52e14356386030d8958ae8b1761d2325Patch
- https://git.kernel.org/stable/c/d570c48dd37dbe8fc6875d4461d01a9554ae2560Patch
- https://git.kernel.org/stable/c/067c694d06040db6f0c65281bb358452ca6d85b9Patch
- https://git.kernel.org/stable/c/3b0c406124719b625b1aba431659f5cdc24a982cPatch
- https://git.kernel.org/stable/c/699d926585daa6ec44be556cdc1ab89e5d54557bPatch
- https://git.kernel.org/stable/c/70aed03b1d5a5df974f456cdc8eedb213c94bb8bPatch
- https://git.kernel.org/stable/c/7e71fcedfda6f7de18f850a6b36e78d78b04476fPatch
- https://git.kernel.org/stable/c/883f7897a25e3ce14a7f274ca4c73f49ac84002aPatch
- https://git.kernel.org/stable/c/8a6a240f52e14356386030d8958ae8b1761d2325Patch
- https://git.kernel.org/stable/c/d570c48dd37dbe8fc6875d4461d01a9554ae2560Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.