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| author |   Laurent Vivier <lvivier@redhat.com> | 2019-10-14 13:46:32 +0200 |
|---|---|---|
| committer |   Herbert Xu <herbert@gondor.apana.org.au> | 2019-10-23 19:47:00 +1100 |
| commit | 28443671a468489fb147b31687b2157b6ba59c4a (patch) | |
| tree | e9fe658a20ac17216e716945ef1ea817aa99484e /drivers/crypto/hisilicon | |
| parent | crypto: nx - convert AES-CTR to skcipher API (diff) | |
| download | linux-dev-28443671a468489fb147b31687b2157b6ba59c4a.tar.xz linux-dev-28443671a468489fb147b31687b2157b6ba59c4a.zip | |
hwrng: core - Fix use-after-free warning in hwrng_register()
Commit daae28debcb0 has moved add_early_randomness() out of the
rng_mutex and tries to protect the reference of the new rng device
by incrementing the reference counter.
But in hwrng_register(), the function can be called with a new device
that is not set as the current_rng device and the reference has not been
initialized. This patch fixes the problem by not using the reference
counter when the device is not the current one: the reference counter
is only meaningful in the case of the current rng device and a device
is not used if it is not the current one (except in hwrng_register())
The problem has been reported by Marek Szyprowski on ARM 32bit
Exynos5420-based Chromebook Peach-Pit board:
WARNING: CPU: 3 PID: 1 at lib/refcount.c:156 hwrng_register+0x13c/0x1b4
refcount_t: increment on 0; use-after-free.
Modules linked in:
CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.4.0-rc1-00061-gdaae28debcb0
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[<c01124c8>] (unwind_backtrace) from [<c010dfb8>] (show_stack+0x10/0x14)
[<c010dfb8>] (show_stack) from [<c0ae86d8>] (dump_stack+0xa8/0xd4)
[<c0ae86d8>] (dump_stack) from [<c0127428>] (__warn+0xf4/0x10c)
[<c0127428>] (__warn) from [<c01274b4>] (warn_slowpath_fmt+0x74/0xb8)
[<c01274b4>] (warn_slowpath_fmt) from [<c054729c>] (hwrng_register+0x13c/0x1b4)
[<c054729c>] (hwrng_register) from [<c0547e54>] (tpm_chip_register+0xc4/0x274)
...
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: daae28debcb0 ("hwrng: core - move add_early_randomness() out of rng_mutex")
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers/crypto/hisilicon')
0 files changed, 0 insertions, 0 deletions