fix: allow dag import of 1MiB chunks wrapped in dag-pb

core/commands/add.go

@@ -172,6 +172,16 @@ Buzhash or Rabin fingerprint chunker for content defined chunking by
 specifying buzhash or rabin-[min]-[avg]-[max] (where min/avg/max refer
 to the desired chunk sizes in bytes), e.g. 'rabin-262144-524288-1048576'.
 
+The maximum accepted value for 'size-N' and rabin 'max' parameter is
+2MiB minus 256 bytes (2096896 bytes). The 256-byte overhead budget is
+reserved for protobuf/UnixFS framing so that serialized blocks stay
+within the 2MiB block size limit from the bitswap spec. The buzhash
+chunker uses a fixed internal maximum of 512KiB and is not affected.
+
+Only the fixed-size chunker ('size-N') guarantees that the same data
+will always produce the same CID. The rabin and buzhash chunkers may
+change their internal parameters in a future release.
+
 The following examples use very small byte sizes to demonstrate the
 properties of the different chunkers on a small file. You'll likely
 want to use a 1024 times larger chunk sizes for most files.

core/commands/cmdutils/utils.go

@@ -14,14 +14,16 @@ import (
 
 const (
 	AllowBigBlockOptionName = "allow-big-block"
-	SoftBlockLimit          = 1024 * 1024 // https://github.com/ipfs/kubo/issues/7421#issuecomment-910833499
-	MaxPinNameBytes         = 255         // Maximum number of bytes allowed for a pin name
+	// SoftBlockLimit is the maximum block size for bitswap transfer.
+	// If this value changes, update the "2MiB" strings in error messages below.
+	SoftBlockLimit  = 2 * 1024 * 1024 // https://specs.ipfs.tech/bitswap-protocol/#block-sizes
+	MaxPinNameBytes = 255             // Maximum number of bytes allowed for a pin name
 )
 
 var AllowBigBlockOption cmds.Option
 
 func init() {
-	AllowBigBlockOption = cmds.BoolOption(AllowBigBlockOptionName, "Disable block size check and allow creation of blocks bigger than 1MiB. WARNING: such blocks won't be transferable over the standard bitswap.").WithDefault(false)
+	AllowBigBlockOption = cmds.BoolOption(AllowBigBlockOptionName, "Disable block size check and allow creation of blocks bigger than 2MiB. WARNING: such blocks won't be transferable over the standard bitswap.").WithDefault(false)
 }
 
 func CheckCIDSize(req *cmds.Request, c cid.Cid, dagAPI coreiface.APIDagService) error {
@@ -44,11 +46,10 @@ func CheckBlockSize(req *cmds.Request, size uint64) error {
 		return nil
 	}
 
-	// We do not allow producing blocks bigger than 1 MiB to avoid errors
-	// when transmitting them over BitSwap. The 1 MiB constant is an
-	// unenforced and undeclared rule of thumb hard-coded here.
+	// Block size is limited to SoftBlockLimit (2MiB) as defined in the bitswap spec.
+	// https://specs.ipfs.tech/bitswap-protocol/#block-sizes
 	if size > SoftBlockLimit {
-		return fmt.Errorf("produced block is over 1MiB: big blocks can't be exchanged with other peers. consider using UnixFS for automatic chunking of bigger files, or pass --allow-big-block to override")
+		return fmt.Errorf("produced block is over 2MiB: big blocks can't be exchanged with other peers. consider using UnixFS for automatic chunking of bigger files, or pass --allow-big-block to override")
 	}
 	return nil
 }

docs/changelogs/v0.40.md

@@ -67,6 +67,10 @@ The `test-cid-v1` and `test-cid-v1-wide` profiles have been removed. Use `unixfs
 
 When writing to MFS directories that use CIDv1 (via `--cid-version=1` or `ipfs files chcid`), single-block files now produce raw block CIDs (like `bafkrei...`), matching the behavior of `ipfs add --raw-leaves`. Previously, MFS would wrap single-block files in dag-pb even when raw leaves were enabled. CIDv0 directories continue to use dag-pb.
 
+**Block size limit raised to 2MiB**
+
+`ipfs block put`, `ipfs dag put`, and `ipfs dag import` now accept blocks up to 2MiB without `--allow-big-block`, matching the [bitswap spec](https://specs.ipfs.tech/bitswap-protocol/#block-sizes). The previous 1MiB limit was too restrictive and broke `ipfs dag import` of 1MiB-chunked non-raw-leaf data (protobuf wrapping pushes blocks slightly over 1MiB). The max `--chunker` value for `ipfs add` is `2MiB - 256 bytes` to leave room for protobuf framing. IPIP-499 profiles use lower chunk sizes (256KiB and 1MiB) and are not affected.
+
 **HAMT Threshold Fix**
 
 HAMT directory sharding threshold changed from `>=` to `>` to match the Go docs and JS implementation ([ipfs/boxo@6707376](https://github.com/ipfs/boxo/commit/6707376002a3d4ba64895749ce9be2e00d265ed5)). A directory exactly at 256 KiB now stays as a basic directory instead of converting to HAMT. This is a theoretical breaking change, but unlikely to impact real-world users as it requires a directory to be exactly at the threshold boundary. If you depend on the old behavior, adjust [`Import.UnixFSHAMTShardingSize`](https://github.com/ipfs/kubo/blob/master/docs/config.md#importunixfshamtshardingsize) to be 1 byte lower.

docs/config.md

@@ -3716,9 +3716,21 @@ The default UnixFS chunker. Commands affected: `ipfs add`.
 Valid formats:
 
 - `size-<bytes>` - fixed size chunker
-- `rabin-<min>-<avg>-<max>` - rabin fingerprint chunker  
+- `rabin-<min>-<avg>-<max>` - rabin fingerprint chunker
 - `buzhash` - buzhash chunker
 
+The maximum accepted value for `size-<bytes>` and rabin `max` parameter is
+`2MiB - 256 bytes` (2096896 bytes). The 256-byte overhead budget is reserved
+for protobuf/UnixFS framing so that serialized blocks stay within the 2MiB
+block size limit defined by the
+[bitswap spec](https://specs.ipfs.tech/bitswap-protocol/#block-sizes).
+The `buzhash` chunker uses a fixed internal maximum of 512KiB and is not
+affected by this limit.
+
+Only the fixed-size chunker (`size-<bytes>`) guarantees that the same data
+will always produce the same CID. The `rabin` and `buzhash` chunkers may
+change their internal parameters in a future release.
+
 Default: `size-262144`
 
 Type: `optionalString`

docs/examples/kubo-as-a-library/go.mod

@@ -7,7 +7,7 @@ go 1.25
 replace github.com/ipfs/kubo => ./../../..
 
 require (
-	github.com/ipfs/boxo v0.36.1-0.20260205235512-2a942e3e1a75
+	github.com/ipfs/boxo v0.36.1-0.20260206224221-77bd614971f0
 	github.com/ipfs/kubo v0.0.0-00010101000000-000000000000
 	github.com/libp2p/go-libp2p v0.47.0
 	github.com/multiformats/go-multiaddr v0.16.1

docs/examples/kubo-as-a-library/go.sum

@@ -267,8 +267,8 @@ github.com/ipfs-shipyard/nopfs/ipfs v0.25.0 h1:OqNqsGZPX8zh3eFMO8Lf8EHRRnSGBMqcd
 github.com/ipfs-shipyard/nopfs/ipfs v0.25.0/go.mod h1:BxhUdtBgOXg1B+gAPEplkg/GpyTZY+kCMSfsJvvydqU=
 github.com/ipfs/bbloom v0.0.4 h1:Gi+8EGJ2y5qiD5FbsbpX/TMNcJw8gSqr7eyjHa4Fhvs=
 github.com/ipfs/bbloom v0.0.4/go.mod h1:cS9YprKXpoZ9lT0n/Mw/a6/aFV6DTjTLYHeA+gyqMG0=
-github.com/ipfs/boxo v0.36.1-0.20260205235512-2a942e3e1a75 h1:1UoSAzXwwgOrCZm5cu6v6bL4OGYIzcaOew9Rl6ZycqQ=
-github.com/ipfs/boxo v0.36.1-0.20260205235512-2a942e3e1a75/go.mod h1:92hnRXfP5ScKEIqlq9Ns7LR1dFXEVADKWVGH0fjk83k=
+github.com/ipfs/boxo v0.36.1-0.20260206224221-77bd614971f0 h1:tC8iJdzsCy/npaez/gtQqNDLpl7DBqCARj9AECmYmoI=
+github.com/ipfs/boxo v0.36.1-0.20260206224221-77bd614971f0/go.mod h1:92hnRXfP5ScKEIqlq9Ns7LR1dFXEVADKWVGH0fjk83k=
 github.com/ipfs/go-bitfield v1.1.0 h1:fh7FIo8bSwaJEh6DdTWbCeZ1eqOaOkKFI74SCnsWbGA=
 github.com/ipfs/go-bitfield v1.1.0/go.mod h1:paqf1wjq/D2BBmzfTVFlJQ9IlFOZpg422HL0HqsGWHU=
 github.com/ipfs/go-block-format v0.0.3/go.mod h1:4LmD4ZUw0mhO+JSKdpWwrzATiEfM7WWgQ8H5l6P8MVk=

go.mod

@@ -21,7 +21,7 @@ require (
 	github.com/hashicorp/go-version v1.8.0
 	github.com/ipfs-shipyard/nopfs v0.0.14
 	github.com/ipfs-shipyard/nopfs/ipfs v0.25.0
-	github.com/ipfs/boxo v0.36.1-0.20260205235512-2a942e3e1a75
+	github.com/ipfs/boxo v0.36.1-0.20260206224221-77bd614971f0
 	github.com/ipfs/go-block-format v0.2.3
 	github.com/ipfs/go-cid v0.6.0
 	github.com/ipfs/go-cidutil v0.1.0
@@ -274,6 +274,7 @@ require (
 )
 
 // Exclude ancient +incompatible versions that confuse Dependabot.
+
 // These pre-Go-modules versions reference packages that no longer exist.
 exclude (
 	github.com/ipfs/go-ipfs-cmds v2.0.1+incompatible

go.sum

@@ -337,8 +337,8 @@ github.com/ipfs-shipyard/nopfs/ipfs v0.25.0 h1:OqNqsGZPX8zh3eFMO8Lf8EHRRnSGBMqcd
 github.com/ipfs-shipyard/nopfs/ipfs v0.25.0/go.mod h1:BxhUdtBgOXg1B+gAPEplkg/GpyTZY+kCMSfsJvvydqU=
 github.com/ipfs/bbloom v0.0.4 h1:Gi+8EGJ2y5qiD5FbsbpX/TMNcJw8gSqr7eyjHa4Fhvs=
 github.com/ipfs/bbloom v0.0.4/go.mod h1:cS9YprKXpoZ9lT0n/Mw/a6/aFV6DTjTLYHeA+gyqMG0=
-github.com/ipfs/boxo v0.36.1-0.20260205235512-2a942e3e1a75 h1:1UoSAzXwwgOrCZm5cu6v6bL4OGYIzcaOew9Rl6ZycqQ=
-github.com/ipfs/boxo v0.36.1-0.20260205235512-2a942e3e1a75/go.mod h1:92hnRXfP5ScKEIqlq9Ns7LR1dFXEVADKWVGH0fjk83k=
+github.com/ipfs/boxo v0.36.1-0.20260206224221-77bd614971f0 h1:tC8iJdzsCy/npaez/gtQqNDLpl7DBqCARj9AECmYmoI=
+github.com/ipfs/boxo v0.36.1-0.20260206224221-77bd614971f0/go.mod h1:92hnRXfP5ScKEIqlq9Ns7LR1dFXEVADKWVGH0fjk83k=
 github.com/ipfs/go-bitfield v1.1.0 h1:fh7FIo8bSwaJEh6DdTWbCeZ1eqOaOkKFI74SCnsWbGA=
 github.com/ipfs/go-bitfield v1.1.0/go.mod h1:paqf1wjq/D2BBmzfTVFlJQ9IlFOZpg422HL0HqsGWHU=
 github.com/ipfs/go-block-format v0.0.3/go.mod h1:4LmD4ZUw0mhO+JSKdpWwrzATiEfM7WWgQ8H5l6P8MVk=