From: Brendan Jackman jackmanb@google.com
mainline inclusion from mainline-5.12-rc1 commit c6458e72f6fd6ac7e390da0d9abe8446084886e5 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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When the buffer is too small to contain the input string, these helpers return the length of the buffer, not the length of the original string. This tries to make the docs totally clear about that, since "the length of the [copied ]string" could also refer to the length of the input.
Signed-off-by: Brendan Jackman jackmanb@google.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: KP Singh kpsingh@kernel.org Acked-by: Yonghong Song yhs@fb.com Link: https://lore.kernel.org/bpf/20210112123422.2011234-1-jackmanb@google.com (cherry picked from commit c6458e72f6fd6ac7e390da0d9abe8446084886e5) Signed-off-by: Wang Yufen wangyufen@huawei.com --- include/uapi/linux/bpf.h | 10 +++++----- tools/include/uapi/linux/bpf.h | 10 +++++----- 2 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 241f26f52a64..04f78c6cd567 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -2994,10 +2994,10 @@ union bpf_attr { * string length is larger than *size*, just *size*-1 bytes are * copied and the last byte is set to NUL. * - * On success, the length of the copied string is returned. This - * makes this helper useful in tracing programs for reading - * strings, and more importantly to get its length at runtime. See - * the following snippet: + * On success, returns the number of bytes that were written, + * including the terminal NUL. This makes this helper useful in + * tracing programs for reading strings, and more importantly to + * get its length at runtime. See the following snippet: * * :: * @@ -3025,7 +3025,7 @@ union bpf_attr { * **->mm->env_start**: using this helper and the return value, * one can quickly iterate at the right offset of the memory area. * Return - * On success, the strictly positive length of the string, + * On success, the strictly positive length of the output string, * including the trailing NUL character. On error, a negative * value. * diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 9d885ea960f0..acdc91cd5d6b 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -2994,10 +2994,10 @@ union bpf_attr { * string length is larger than *size*, just *size*-1 bytes are * copied and the last byte is set to NUL. * - * On success, the length of the copied string is returned. This - * makes this helper useful in tracing programs for reading - * strings, and more importantly to get its length at runtime. See - * the following snippet: + * On success, returns the number of bytes that were written, + * including the terminal NUL. This makes this helper useful in + * tracing programs for reading strings, and more importantly to + * get its length at runtime. See the following snippet: * * :: * @@ -3025,7 +3025,7 @@ union bpf_attr { * **->mm->env_start**: using this helper and the return value, * one can quickly iterate at the right offset of the memory area. * Return - * On success, the strictly positive length of the string, + * On success, the strictly positive length of the output string, * including the trailing NUL character. On error, a negative * value. *