| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2022-48821: misc: fastrpc: avoid double fput() on failed usercopy |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| misc: fastrpc: avoid double fput() on failed usercopy |
| |
| If the copy back to userland fails for the FASTRPC_IOCTL_ALLOC_DMA_BUFF |
| ioctl(), we shouldn't assume that 'buf->dmabuf' is still valid. In fact, |
| dma_buf_fd() called fd_install() before, i.e. "consumed" one reference, |
| leaving us with none. |
| |
| Calling dma_buf_put() will therefore put a reference we no longer own, |
| leading to a valid file descritor table entry for an already released |
| 'file' object which is a straight use-after-free. |
| |
| Simply avoid calling dma_buf_put() and rely on the process exit code to |
| do the necessary cleanup, if needed, i.e. if the file descriptor is |
| still valid. |
| |
| The Linux kernel CVE team has assigned CVE-2022-48821 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.1 with commit 6cffd79504ce040f460831030d3069fa1c99bb71 and fixed in 5.4.180 with commit 4e6fd2b5fcf8e7119305a6042bd92e7f2b9ed215 |
| Issue introduced in 5.1 with commit 6cffd79504ce040f460831030d3069fa1c99bb71 and fixed in 5.10.101 with commit a5ce7ee5fcc07583159f54ab4af5164de00148f5 |
| Issue introduced in 5.1 with commit 6cffd79504ce040f460831030d3069fa1c99bb71 and fixed in 5.15.24 with commit e4382d0a39f9a1e260d62fdc079ddae5293c037d |
| Issue introduced in 5.1 with commit 6cffd79504ce040f460831030d3069fa1c99bb71 and fixed in 5.16.10 with commit 76f85c307ef9f10aa2cef1b1d5ee654c1f3345fc |
| Issue introduced in 5.1 with commit 6cffd79504ce040f460831030d3069fa1c99bb71 and fixed in 5.17 with commit 46963e2e0629cb31c96b1d47ddd89dc3d8990b34 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2022-48821 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/misc/fastrpc.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/4e6fd2b5fcf8e7119305a6042bd92e7f2b9ed215 |
| https://git.kernel.org/stable/c/a5ce7ee5fcc07583159f54ab4af5164de00148f5 |
| https://git.kernel.org/stable/c/e4382d0a39f9a1e260d62fdc079ddae5293c037d |
| https://git.kernel.org/stable/c/76f85c307ef9f10aa2cef1b1d5ee654c1f3345fc |
| https://git.kernel.org/stable/c/46963e2e0629cb31c96b1d47ddd89dc3d8990b34 |
