bpf: widen dynptr size/offset to 64 bit

Dynptr currently caps size and offset at 24 bits, which isn’t sufficient
for file-backed use cases; even 32 bits can be limiting. Refactor dynptr
helpers/kfuncs to use 64-bit size and offset, ensuring consistency
across the APIs.

This change does not affect internals of xdp, skb or other dynptrs,
which continue to behave as before. Also it does not break binary
compatibility.

The widening enables large-file access support via dynptr, implemented
in the next patches.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251026203853.135105-3-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 23 insertions, 23 deletions

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 4f87c16d915a..a795f7afbf3d 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -3372,13 +3372,13 @@ typedef int (*copy_fn_t)(void *dst, const void *src, u32 size, struct task_struc
  * direct calls into all the specific callback implementations
  * (copy_user_data_sleepable, copy_user_data_nofault, and so on)
  */
-static __always_inline int __bpf_dynptr_copy_str(struct bpf_dynptr *dptr, u32 doff, u32 size,
+static __always_inline int __bpf_dynptr_copy_str(struct bpf_dynptr *dptr, u64 doff, u64 size,
 						 const void *unsafe_src,
 						 copy_fn_t str_copy_fn,
 						 struct task_struct *tsk)
 {
 	struct bpf_dynptr_kern *dst;
-	u32 chunk_sz, off;
+	u64 chunk_sz, off;
 	void *dst_slice;
 	int cnt, err;
 	char buf[256];
@@ -3392,7 +3392,7 @@ static __always_inline int __bpf_dynptr_copy_str(struct bpf_dynptr *dptr, u32 do
 		return -E2BIG;
 
 	for (off = 0; off < size; off += chunk_sz - 1) {
-		chunk_sz = min_t(u32, sizeof(buf), size - off);
+		chunk_sz = min_t(u64, sizeof(buf), size - off);
 		/* Expect str_copy_fn to return count of copied bytes, including
 		 * zero terminator. Next iteration increment off by chunk_sz - 1 to
 		 * overwrite NUL.
@@ -3409,14 +3409,14 @@ static __always_inline int __bpf_dynptr_copy_str(struct bpf_dynptr *dptr, u32 do
 	return off;
 }
 
-static __always_inline int __bpf_dynptr_copy(const struct bpf_dynptr *dptr, u32 doff,
-					     u32 size, const void *unsafe_src,
+static __always_inline int __bpf_dynptr_copy(const struct bpf_dynptr *dptr, u64 doff,
+					     u64 size, const void *unsafe_src,
 					     copy_fn_t copy_fn, struct task_struct *tsk)
 {
 	struct bpf_dynptr_kern *dst;
 	void *dst_slice;
 	char buf[256];
-	u32 off, chunk_sz;
+	u64 off, chunk_sz;
 	int err;
 
 	dst_slice = bpf_dynptr_slice_rdwr(dptr, doff, NULL, size);
@@ -3428,7 +3428,7 @@ static __always_inline int __bpf_dynptr_copy(const struct bpf_dynptr *dptr, u32
 		return -E2BIG;
 
 	for (off = 0; off < size; off += chunk_sz) {
-		chunk_sz = min_t(u32, sizeof(buf), size - off);
+		chunk_sz = min_t(u64, sizeof(buf), size - off);
 		err = copy_fn(buf, unsafe_src + off, chunk_sz, tsk);
 		if (err)
 			return err;
@@ -3514,58 +3514,58 @@ __bpf_kfunc int bpf_send_signal_task(struct task_struct *task, int sig, enum pid
 	return bpf_send_signal_common(sig, type, task, value);
 }
 
-__bpf_kfunc int bpf_probe_read_user_dynptr(struct bpf_dynptr *dptr, u32 off,
-					   u32 size, const void __user *unsafe_ptr__ign)
+__bpf_kfunc int bpf_probe_read_user_dynptr(struct bpf_dynptr *dptr, u64 off,
+					   u64 size, const void __user *unsafe_ptr__ign)
 {
 	return __bpf_dynptr_copy(dptr, off, size, (const void *)unsafe_ptr__ign,
 				 copy_user_data_nofault, NULL);
 }
 
-__bpf_kfunc int bpf_probe_read_kernel_dynptr(struct bpf_dynptr *dptr, u32 off,
-					     u32 size, const void *unsafe_ptr__ign)
+__bpf_kfunc int bpf_probe_read_kernel_dynptr(struct bpf_dynptr *dptr, u64 off,
+					     u64 size, const void *unsafe_ptr__ign)
 {
 	return __bpf_dynptr_copy(dptr, off, size, unsafe_ptr__ign,
 				 copy_kernel_data_nofault, NULL);
 }
 
-__bpf_kfunc int bpf_probe_read_user_str_dynptr(struct bpf_dynptr *dptr, u32 off,
-					       u32 size, const void __user *unsafe_ptr__ign)
+__bpf_kfunc int bpf_probe_read_user_str_dynptr(struct bpf_dynptr *dptr, u64 off,
+					       u64 size, const void __user *unsafe_ptr__ign)
 {
 	return __bpf_dynptr_copy_str(dptr, off, size, (const void *)unsafe_ptr__ign,
 				     copy_user_str_nofault, NULL);
 }
 
-__bpf_kfunc int bpf_probe_read_kernel_str_dynptr(struct bpf_dynptr *dptr, u32 off,
-						 u32 size, const void *unsafe_ptr__ign)
+__bpf_kfunc int bpf_probe_read_kernel_str_dynptr(struct bpf_dynptr *dptr, u64 off,
+						 u64 size, const void *unsafe_ptr__ign)
 {
 	return __bpf_dynptr_copy_str(dptr, off, size, unsafe_ptr__ign,
 				     copy_kernel_str_nofault, NULL);
 }
 
-__bpf_kfunc int bpf_copy_from_user_dynptr(struct bpf_dynptr *dptr, u32 off,
-					  u32 size, const void __user *unsafe_ptr__ign)
+__bpf_kfunc int bpf_copy_from_user_dynptr(struct bpf_dynptr *dptr, u64 off,
+					  u64 size, const void __user *unsafe_ptr__ign)
 {
 	return __bpf_dynptr_copy(dptr, off, size, (const void *)unsafe_ptr__ign,
 				 copy_user_data_sleepable, NULL);
 }
 
-__bpf_kfunc int bpf_copy_from_user_str_dynptr(struct bpf_dynptr *dptr, u32 off,
-					      u32 size, const void __user *unsafe_ptr__ign)
+__bpf_kfunc int bpf_copy_from_user_str_dynptr(struct bpf_dynptr *dptr, u64 off,
+					      u64 size, const void __user *unsafe_ptr__ign)
 {
 	return __bpf_dynptr_copy_str(dptr, off, size, (const void *)unsafe_ptr__ign,
 				     copy_user_str_sleepable, NULL);
 }
 
-__bpf_kfunc int bpf_copy_from_user_task_dynptr(struct bpf_dynptr *dptr, u32 off,
-					       u32 size, const void __user *unsafe_ptr__ign,
+__bpf_kfunc int bpf_copy_from_user_task_dynptr(struct bpf_dynptr *dptr, u64 off,
+					       u64 size, const void __user *unsafe_ptr__ign,
 					       struct task_struct *tsk)
 {
 	return __bpf_dynptr_copy(dptr, off, size, (const void *)unsafe_ptr__ign,
 				 copy_user_data_sleepable, tsk);
 }
 
-__bpf_kfunc int bpf_copy_from_user_task_str_dynptr(struct bpf_dynptr *dptr, u32 off,
-						   u32 size, const void __user *unsafe_ptr__ign,
+__bpf_kfunc int bpf_copy_from_user_task_str_dynptr(struct bpf_dynptr *dptr, u64 off,
+						   u64 size, const void __user *unsafe_ptr__ign,
 						   struct task_struct *tsk)
 {
 	return __bpf_dynptr_copy_str(dptr, off, size, (const void *)unsafe_ptr__ign,