diff options
| author | Michael Jeanson <mjeanson@efficios.com> | 2025-02-19 15:53:26 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-02-21 14:21:02 +0100 |
| commit | dc0a241ceaf3b7df6f1a7658b020c92682b75bfc (patch) | |
| tree | 2019cf9195d235456ef28aedd2988ae8c7be36a0 | |
| parent | 02d954c0fdf91845169cdacc7405b120f90afe01 (diff) | |
rseq: Fix rseq registration with CONFIG_DEBUG_RSEQ
With CONFIG_DEBUG_RSEQ=y, at rseq registration the read-only fields are
copied from user-space, if this copy fails the syscall returns -EFAULT
and the registration should not be activated - but it erroneously is.
Move the activation of the registration after the copy of the fields to
fix this bug.
Fixes: 7d5265ffcd8b ("rseq: Validate read-only fields under DEBUG_RSEQ config")
Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/r/20250219205330.324770-1-mjeanson@efficios.com
| -rw-r--r-- | kernel/rseq.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/kernel/rseq.c b/kernel/rseq.c index 442aba29bc4c..2cb16091ec0a 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -507,9 +507,6 @@ SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, return -EINVAL; if (!access_ok(rseq, rseq_len)) return -EFAULT; - current->rseq = rseq; - current->rseq_len = rseq_len; - current->rseq_sig = sig; #ifdef CONFIG_DEBUG_RSEQ /* * Initialize the in-kernel rseq fields copy for validation of @@ -522,6 +519,14 @@ SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len, return -EFAULT; #endif /* + * Activate the registration by setting the rseq area address, length + * and signature in the task struct. + */ + current->rseq = rseq; + current->rseq_len = rseq_len; + current->rseq_sig = sig; + + /* * If rseq was previously inactive, and has just been * registered, ensure the cpu_id_start and cpu_id fields * are updated before returning to user-space. |