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From: Jiri Olsa <jolsa@kernel.org>
To: stable@vger.kernel.org
Cc: "Christoph Hellwig" <hch@lst.de>,
	"John Fastabend" <john.fastabend@gmail.com>,
	linux-mm@kvack.org, bpf@vger.kernel.org, x86@kernel.org,
	linux-kernel@vger.kernel.org,
	"Masami Hiramatsu" <mhiramat@kernel.org>,
	"Tsahee Zidenberg" <tsahee@annapurnalabs.com>,
	"Andrii Nakryiko" <andrii@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Mahé Tardy" <mahe.tardy@isovalent.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH stable 5.4 8/8] bpf: bpf_probe_read_kernel_str() has to return amount of data read on success
Date: Mon, 22 May 2023 22:33:52 +0200	[thread overview]
Message-ID: <20230522203352.738576-9-jolsa@kernel.org> (raw)
In-Reply-To: <20230522203352.738576-1-jolsa@kernel.org>

From: Andrii Nakryiko <andriin@fb.com>

commit 02553b91da5deb63c8562b47529b09b734659af0 upstream.

During recent refactorings, bpf_probe_read_kernel_str() started returning 0 on
success, instead of amount of data successfully read. This majorly breaks
applications relying on bpf_probe_read_kernel_str() and bpf_probe_read_str()
and their results. Fix this by returning actual number of bytes read.

Fixes: 8d92db5c04d1 ("bpf: rework the compat kernel probe handling")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200616050432.1902042-1-andriin@fb.com
---
 kernel/trace/bpf_trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index a46256f99229..c4c825dcdef8 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -198,7 +198,7 @@ bpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr)
 	if (unlikely(ret < 0))
 		goto fail;
 
-	return 0;
+	return ret;
 fail:
 	memset(dst, 0, size);
 	return ret;
-- 
2.40.1


WARNING: multiple messages have this Message-ID (diff)
From: Jiri Olsa <jolsa@kernel.org>
To: stable@vger.kernel.org
Cc: "Christoph Hellwig" <hch@lst.de>,
	"John Fastabend" <john.fastabend@gmail.com>,
	linux-mm@kvack.org, bpf@vger.kernel.org, x86@kernel.org,
	linux-kernel@vger.kernel.org,
	"Masami Hiramatsu" <mhiramat@kernel.org>,
	"Tsahee Zidenberg" <tsahee@annapurnalabs.com>,
	"Andrii Nakryiko" <andrii@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Mahé Tardy" <mahe.tardy@isovalent.com>,
	linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH stable 5.4 8/8] bpf: bpf_probe_read_kernel_str() has to return amount of data read on success
Date: Mon, 22 May 2023 22:33:52 +0200	[thread overview]
Message-ID: <20230522203352.738576-9-jolsa@kernel.org> (raw)
In-Reply-To: <20230522203352.738576-1-jolsa@kernel.org>

From: Andrii Nakryiko <andriin@fb.com>

commit 02553b91da5deb63c8562b47529b09b734659af0 upstream.

During recent refactorings, bpf_probe_read_kernel_str() started returning 0 on
success, instead of amount of data successfully read. This majorly breaks
applications relying on bpf_probe_read_kernel_str() and bpf_probe_read_str()
and their results. Fix this by returning actual number of bytes read.

Fixes: 8d92db5c04d1 ("bpf: rework the compat kernel probe handling")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200616050432.1902042-1-andriin@fb.com
---
 kernel/trace/bpf_trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index a46256f99229..c4c825dcdef8 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -198,7 +198,7 @@ bpf_probe_read_kernel_str_common(void *dst, u32 size, const void *unsafe_ptr)
 	if (unlikely(ret < 0))
 		goto fail;
 
-	return 0;
+	return ret;
 fail:
 	memset(dst, 0, size);
 	return ret;
-- 
2.40.1


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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2023-05-22 20:36 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-22 20:33 [RFC PATCH stable 5.4 0/8] bpf: Fix bpf_probe_read/bpf_probe_read_str helpers Jiri Olsa
2023-05-22 20:33 ` Jiri Olsa
2023-05-22 20:33 ` [RFC PATCH stable 5.4 1/8] uaccess: Add strict non-pagefault kernel-space read function Jiri Olsa
2023-05-22 20:33   ` Jiri Olsa
2023-05-22 20:33 ` [RFC PATCH stable 5.4 2/8] bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers Jiri Olsa
2023-05-22 20:33   ` Jiri Olsa
2023-05-22 20:33 ` [RFC PATCH stable 5.4 3/8] bpf: Restrict bpf_probe_read{, str}() only to archs where they work Jiri Olsa
2023-05-22 20:33   ` Jiri Olsa
2023-05-22 20:33 ` [RFC PATCH stable 5.4 4/8] maccess: clarify kerneldoc comments Jiri Olsa
2023-05-22 20:33   ` Jiri Olsa
2023-05-22 20:33 ` [RFC PATCH stable 5.4 5/8] maccess: rename strncpy_from_unsafe_user to strncpy_from_user_nofault Jiri Olsa
2023-05-22 20:33   ` Jiri Olsa
2023-05-22 20:33 ` [RFC PATCH stable 5.4 6/8] maccess: rename strncpy_from_unsafe_strict to strncpy_from_kernel_nofault Jiri Olsa
2023-05-22 20:33   ` Jiri Olsa
2023-05-22 20:33 ` [RFC PATCH stable 5.4 7/8] bpf: rework the compat kernel probe handling Jiri Olsa
2023-05-22 20:33   ` Jiri Olsa
2023-05-22 20:33 ` Jiri Olsa [this message]
2023-05-22 20:33   ` [RFC PATCH stable 5.4 8/8] bpf: bpf_probe_read_kernel_str() has to return amount of data read on success Jiri Olsa
2023-05-26 18:54 ` [RFC PATCH stable 5.4 0/8] bpf: Fix bpf_probe_read/bpf_probe_read_str helpers Greg KH
2023-05-26 18:54   ` Greg KH
2023-05-28 20:02   ` Jiri Olsa
2023-05-28 20:02     ` Jiri Olsa
2023-05-29  8:37     ` Greg KH
2023-05-29  8:37       ` Greg KH

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