From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Josh Poimboeuf <jpoimboe@redhat.com>,
Borislav Petkov <bp@suse.de>,
Thomas Gleixner <tglx@linutronix.de>,
Frank van der Linden <fllinden@amazon.com>
Subject: [PATCH 4.19 06/33] x86/speculation: Include unprivileged eBPF status in Spectre v2 mitigation reporting
Date: Thu, 10 Mar 2022 15:18:33 +0100 [thread overview]
Message-ID: <20220310140807.936441952@linuxfoundation.org> (raw)
In-Reply-To: <20220310140807.749164737@linuxfoundation.org>
From: Josh Poimboeuf <jpoimboe@redhat.com>
commit 44a3918c8245ab10c6c9719dd12e7a8d291980d8 upstream.
With unprivileged eBPF enabled, eIBRS (without retpoline) is vulnerable
to Spectre v2 BHB-based attacks.
When both are enabled, print a warning message and report it in the
'spectre_v2' sysfs vulnerabilities file.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
[fllinden@amazon.com: backported to 4.19]
Signed-off-by: Frank van der Linden <fllinden@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/kernel/cpu/bugs.c | 35 +++++++++++++++++++++++++++++------
include/linux/bpf.h | 11 +++++++++++
kernel/sysctl.c | 8 ++++++++
3 files changed, 48 insertions(+), 6 deletions(-)
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -31,6 +31,7 @@
#include <asm/intel-family.h>
#include <asm/e820/api.h>
#include <asm/hypervisor.h>
+#include <linux/bpf.h>
#include "cpu.h"
@@ -607,6 +608,16 @@ static inline const char *spectre_v2_mod
static inline const char *spectre_v2_module_string(void) { return ""; }
#endif
+#define SPECTRE_V2_EIBRS_EBPF_MSG "WARNING: Unprivileged eBPF is enabled with eIBRS on, data leaks possible via Spectre v2 BHB attacks!\n"
+
+#ifdef CONFIG_BPF_SYSCALL
+void unpriv_ebpf_notify(int new_state)
+{
+ if (spectre_v2_enabled == SPECTRE_V2_EIBRS && !new_state)
+ pr_err(SPECTRE_V2_EIBRS_EBPF_MSG);
+}
+#endif
+
static inline bool match_option(const char *arg, int arglen, const char *opt)
{
int len = strlen(opt);
@@ -950,6 +961,9 @@ static void __init spectre_v2_select_mit
break;
}
+ if (mode == SPECTRE_V2_EIBRS && unprivileged_ebpf_enabled())
+ pr_err(SPECTRE_V2_EIBRS_EBPF_MSG);
+
if (spectre_v2_in_eibrs_mode(mode)) {
/* Force it so VMEXIT will restore correctly */
x86_spec_ctrl_base |= SPEC_CTRL_IBRS;
@@ -1685,6 +1699,20 @@ static char *ibpb_state(void)
return "";
}
+static ssize_t spectre_v2_show_state(char *buf)
+{
+ if (spectre_v2_enabled == SPECTRE_V2_EIBRS && unprivileged_ebpf_enabled())
+ return sprintf(buf, "Vulnerable: Unprivileged eBPF enabled\n");
+
+ return sprintf(buf, "%s%s%s%s%s%s\n",
+ spectre_v2_strings[spectre_v2_enabled],
+ ibpb_state(),
+ boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
+ stibp_state(),
+ boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "",
+ spectre_v2_module_string());
+}
+
static ssize_t srbds_show_state(char *buf)
{
return sprintf(buf, "%s\n", srbds_strings[srbds_mitigation]);
@@ -1710,12 +1738,7 @@ static ssize_t cpu_show_common(struct de
return sprintf(buf, "%s\n", spectre_v1_strings[spectre_v1_mitigation]);
case X86_BUG_SPECTRE_V2:
- return sprintf(buf, "%s%s%s%s%s%s\n", spectre_v2_strings[spectre_v2_enabled],
- ibpb_state(),
- boot_cpu_has(X86_FEATURE_USE_IBRS_FW) ? ", IBRS_FW" : "",
- stibp_state(),
- boot_cpu_has(X86_FEATURE_RSB_CTXSW) ? ", RSB filling" : "",
- spectre_v2_module_string());
+ return spectre_v2_show_state(buf);
case X86_BUG_SPEC_STORE_BYPASS:
return sprintf(buf, "%s\n", ssb_strings[ssb_mode]);
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -533,6 +533,11 @@ static inline int bpf_map_attr_numa_node
struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type type);
int array_map_alloc_check(union bpf_attr *attr);
+static inline bool unprivileged_ebpf_enabled(void)
+{
+ return !sysctl_unprivileged_bpf_disabled;
+}
+
#else /* !CONFIG_BPF_SYSCALL */
static inline struct bpf_prog *bpf_prog_get(u32 ufd)
{
@@ -644,6 +649,12 @@ static inline struct bpf_prog *bpf_prog_
{
return ERR_PTR(-EOPNOTSUPP);
}
+
+static inline bool unprivileged_ebpf_enabled(void)
+{
+ return false;
+}
+
#endif /* CONFIG_BPF_SYSCALL */
static inline struct bpf_prog *bpf_prog_get_type(u32 ufd,
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -251,6 +251,11 @@ static int sysrq_sysctl_handler(struct c
#endif
#ifdef CONFIG_BPF_SYSCALL
+
+void __weak unpriv_ebpf_notify(int new_state)
+{
+}
+
static int bpf_unpriv_handler(struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
@@ -268,6 +273,9 @@ static int bpf_unpriv_handler(struct ctl
return -EPERM;
*(int *)table->data = unpriv_enable;
}
+
+ unpriv_ebpf_notify(unpriv_enable);
+
return ret;
}
#endif
next prev parent reply other threads:[~2022-03-10 14:33 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-10 14:18 [PATCH 4.19 00/33] 4.19.234-rc2 review Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 01/33] x86/speculation: Merge one test in spectre_v2_user_select_mitigation() Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 02/33] x86,bugs: Unconditionally allow spectre_v2=retpoline,amd Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 03/33] x86/speculation: Rename RETPOLINE_AMD to RETPOLINE_LFENCE Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 04/33] x86/speculation: Add eIBRS + Retpoline options Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 05/33] Documentation/hw-vuln: Update spectre doc Greg Kroah-Hartman
2022-03-10 14:18 ` Greg Kroah-Hartman [this message]
2022-03-10 14:18 ` [PATCH 4.19 07/33] x86/speculation: Use generic retpoline by default on AMD Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 08/33] x86/speculation: Update link to AMD speculation whitepaper Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 09/33] x86/speculation: Warn about Spectre v2 LFENCE mitigation Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 10/33] x86/speculation: Warn about eIBRS + LFENCE + Unprivileged eBPF + SMT Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 11/33] arm/arm64: Provide a wrapper for SMCCC 1.1 calls Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 12/33] arm/arm64: smccc/psci: add arm_smccc_1_1_get_conduit() Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 13/33] ARM: report Spectre v2 status through sysfs Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 14/33] ARM: early traps initialisation Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 15/33] ARM: use LOADADDR() to get load address of sections Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 16/33] ARM: Spectre-BHB workaround Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 17/33] ARM: include unprivileged BPF status in Spectre V2 reporting Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 18/33] ARM: fix build error when BPF_SYSCALL is disabled Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 19/33] kbuild: add CONFIG_LD_IS_LLD Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 20/33] ARM: fix co-processor register typo Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 21/33] ARM: Do not use NOCROSSREFS directive with ld.lld Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 22/33] ARM: fix build warning in proc-v7-bugs.c Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 23/33] xen/xenbus: dont let xenbus_grant_ring() remove grants in error case Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 24/33] xen/grant-table: add gnttab_try_end_foreign_access() Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 25/33] xen/blkfront: dont use gnttab_query_foreign_access() for mapped status Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 26/33] xen/netfront: " Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 27/33] xen/scsifront: " Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 28/33] xen/gntalloc: dont use gnttab_query_foreign_access() Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 29/33] xen: remove gnttab_query_foreign_access() Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 30/33] xen/9p: use alloc/free_pages_exact() Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 31/33] xen/pvcalls: " Greg Kroah-Hartman
2022-03-10 14:18 ` [PATCH 4.19 32/33] xen/gnttab: fix gnttab_end_foreign_access() without page specified Greg Kroah-Hartman
2022-03-10 14:19 ` [PATCH 4.19 33/33] xen/netfront: react properly to failing gnttab_end_foreign_access_ref() Greg Kroah-Hartman
2022-03-10 18:00 ` [PATCH 4.19 00/33] 4.19.234-rc2 review Pavel Machek
2022-03-10 18:48 ` Jon Hunter
2022-03-10 19:34 ` Shuah Khan
2022-03-11 1:01 ` Guenter Roeck
2022-03-11 10:09 ` Sudip Mukherjee
2022-03-11 12:32 ` Naresh Kamboju
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