From 33a154a96e71a34a1bcca9f40da343dbbf7b38b4 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 1 Oct 2026 14:52:55 +0000 Subject: selftests/bpf: Test packet range of pointers sharing an id Add tests where two packet pointers share an id and tightening one pointer's umax from its var_off would put it less than their constant distance from the other's umax: with an index & 0x38 capped at 50, the base pointer keeps umax 50, so the pointer 8 bytes further on must keep umax 58, even though its known bits allow at most 56. These refused a valid program or accepted an out-of-bounds access before the fix: - check the advanced copy, load through the base: valid, was refused; - check the base, load the byte at base + 1 through a copy advanced by 8: was accepted; - check base + 4, load 4 bytes at base + 2 through base + 8: reads two bytes past the checked range, was accepted; - the same as the second with data_meta pointers checked against data: was accepted. These pass with and without the fix and cover nearby paths: - subtract an unknown scalar from a checked pointer and load below it (the range is kept across a new id); - reach a load through two paths whose checks cover 8 and 7 bytes after the loaded pointer; the second path must not be pruned by the first; - spill a copy of a pointer, check the pointer, fill the copy and load one byte past the checked range: the load is refused, and the copy has the range of the check. Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20261001145255.855630-2-alexei.starovoitov@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- scripts/coccinelle/api/kvmalloc.cocci | 256 ++++++++++++++++++++++++++++++++++ 1 file changed, 256 insertions(+) create mode 100644 scripts/coccinelle/api/kvmalloc.cocci (limited to 'scripts/coccinelle/api/kvmalloc.cocci') diff --git a/scripts/coccinelle/api/kvmalloc.cocci b/scripts/coccinelle/api/kvmalloc.cocci new file mode 100644 index 000000000..5ddcb76b7 --- /dev/null +++ b/scripts/coccinelle/api/kvmalloc.cocci @@ -0,0 +1,256 @@ +// SPDX-License-Identifier: GPL-2.0-only +/// +/// Find if/else condition with kmalloc/vmalloc calls. +/// Suggest to use kvmalloc instead. Same for kvfree. +/// +// Confidence: High +// Copyright: (C) 2020 Denis Efremov ISPRAS +// Options: --no-includes --include-headers +// + +virtual patch +virtual report +virtual org +virtual context + +@initialize:python@ +@@ +filter = frozenset(['kvfree']) + +def relevant(p): + return not (filter & {el.current_element for el in p}) + +@kvmalloc depends on !patch@ +expression E, E1, size; +identifier flags; +binary operator cmp = {<=, <, ==, >, >=}; +identifier x; +type T; +position p; +@@ + +( +* if (size cmp E1 || ...)@p { + ... +* E = \(kmalloc\|kzalloc\|kcalloc\|kmalloc_node\|kzalloc_node\| +* kmalloc_array\|kmalloc_array_node\|kcalloc_node\) +* (..., size, \(flags\|GFP_KERNEL\|\(GFP_KERNEL\|flags\)|__GFP_NOWARN\), ...) + ... + } else { + ... +* E = \(vmalloc\|vzalloc\|vmalloc_node\|vzalloc_node\)(..., size, ...) + ... + } +| +* E = \(kmalloc\|kzalloc\|kcalloc\|kmalloc_node\|kzalloc_node\| +* kmalloc_array\|kmalloc_array_node\|kcalloc_node\) +* (..., size, \(flags\|GFP_KERNEL\|\(GFP_KERNEL\|flags\)|__GFP_NOWARN\), ...) + ... when != E = E1 + when != size = E1 + when any +* if (E == NULL)@p { + ... +* E = \(vmalloc\|vzalloc\|vmalloc_node\|vzalloc_node\)(..., size, ...) + ... + } +| +* T x = \(kmalloc\|kzalloc\|kcalloc\|kmalloc_node\|kzalloc_node\| +* kmalloc_array\|kmalloc_array_node\|kcalloc_node\) +* (..., size, \(flags\|GFP_KERNEL\|\(GFP_KERNEL\|flags\)|__GFP_NOWARN\), ...); + ... when != x = E1 + when != size = E1 + when any +* if (x == NULL)@p { + ... +* x = \(vmalloc\|vzalloc\|vmalloc_node\|vzalloc_node\)(..., size, ...) + ... + } +) + +@kvfree depends on !patch@ +expression E; +position p : script:python() { relevant(p) }; +@@ + +* if (is_vmalloc_addr(E))@p { + ... +* vfree(E) + ... + } else { + ... when != krealloc(E, ...) + when any +* \(kfree\|kfree_sensitive\)(E) + ... + } + +@depends on patch@ +expression E, E1, size, node; +binary operator cmp = {<=, <, ==, >, >=}; +identifier flags, x; +type T; +@@ + +( +- if (size cmp E1) +- E = kmalloc(size, flags); +- else +- E = vmalloc(size); ++ E = kvmalloc(size, flags); +| +- if (size cmp E1) +- E = kmalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\)); +- else +- E = vmalloc(size); ++ E = kvmalloc(size, GFP_KERNEL); +| +- E = kmalloc(size, flags | __GFP_NOWARN); +- if (E == NULL) +- E = vmalloc(size); ++ E = kvmalloc(size, flags); +| +- E = kmalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\)); +- if (E == NULL) +- E = vmalloc(size); ++ E = kvmalloc(size, GFP_KERNEL); +| +- T x = kmalloc(size, flags | __GFP_NOWARN); +- if (x == NULL) +- x = vmalloc(size); ++ T x = kvmalloc(size, flags); +| +- T x = kmalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\)); +- if (x == NULL) +- x = vmalloc(size); ++ T x = kvmalloc(size, GFP_KERNEL); +| +- if (size cmp E1) +- E = kzalloc(size, flags); +- else +- E = vzalloc(size); ++ E = kvzalloc(size, flags); +| +- if (size cmp E1) +- E = kzalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\)); +- else +- E = vzalloc(size); ++ E = kvzalloc(size, GFP_KERNEL); +| +- E = kzalloc(size, flags | __GFP_NOWARN); +- if (E == NULL) +- E = vzalloc(size); ++ E = kvzalloc(size, flags); +| +- E = kzalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\)); +- if (E == NULL) +- E = vzalloc(size); ++ E = kvzalloc(size, GFP_KERNEL); +| +- T x = kzalloc(size, flags | __GFP_NOWARN); +- if (x == NULL) +- x = vzalloc(size); ++ T x = kvzalloc(size, flags); +| +- T x = kzalloc(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\)); +- if (x == NULL) +- x = vzalloc(size); ++ T x = kvzalloc(size, GFP_KERNEL); +| +- if (size cmp E1) +- E = kmalloc_node(size, flags, node); +- else +- E = vmalloc_node(size, node); ++ E = kvmalloc_node(size, flags, node); +| +- if (size cmp E1) +- E = kmalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node); +- else +- E = vmalloc_node(size, node); ++ E = kvmalloc_node(size, GFP_KERNEL, node); +| +- E = kmalloc_node(size, flags | __GFP_NOWARN, node); +- if (E == NULL) +- E = vmalloc_node(size, node); ++ E = kvmalloc_node(size, flags, node); +| +- E = kmalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node); +- if (E == NULL) +- E = vmalloc_node(size, node); ++ E = kvmalloc_node(size, GFP_KERNEL, node); +| +- T x = kmalloc_node(size, flags | __GFP_NOWARN, node); +- if (x == NULL) +- x = vmalloc_node(size, node); ++ T x = kvmalloc_node(size, flags, node); +| +- T x = kmalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node); +- if (x == NULL) +- x = vmalloc_node(size, node); ++ T x = kvmalloc_node(size, GFP_KERNEL, node); +| +- if (size cmp E1) +- E = kvzalloc_node(size, flags, node); +- else +- E = vzalloc_node(size, node); ++ E = kvzalloc_node(size, flags, node); +| +- if (size cmp E1) +- E = kvzalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node); +- else +- E = vzalloc_node(size, node); ++ E = kvzalloc_node(size, GFP_KERNEL, node); +| +- E = kvzalloc_node(size, flags | __GFP_NOWARN, node); +- if (E == NULL) +- E = vzalloc_node(size, node); ++ E = kvzalloc_node(size, flags, node); +| +- E = kvzalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node); +- if (E == NULL) +- E = vzalloc_node(size, node); ++ E = kvzalloc_node(size, GFP_KERNEL, node); +| +- T x = kvzalloc_node(size, flags | __GFP_NOWARN, node); +- if (x == NULL) +- x = vzalloc_node(size, node); ++ T x = kvzalloc_node(size, flags, node); +| +- T x = kvzalloc_node(size, \(GFP_KERNEL\|GFP_KERNEL|__GFP_NOWARN\), node); +- if (x == NULL) +- x = vzalloc_node(size, node); ++ T x = kvzalloc_node(size, GFP_KERNEL, node); +) + +@depends on patch@ +expression E; +position p : script:python() { relevant(p) }; +@@ + +- if (is_vmalloc_addr(E))@p +- vfree(E); +- else +- kfree(E); ++ kvfree(E); + +@script: python depends on report@ +p << kvmalloc.p; +@@ + +coccilib.report.print_report(p[0], "WARNING opportunity for kvmalloc") + +@script: python depends on org@ +p << kvmalloc.p; +@@ + +coccilib.org.print_todo(p[0], "WARNING opportunity for kvmalloc") + +@script: python depends on report@ +p << kvfree.p; +@@ + +coccilib.report.print_report(p[0], "WARNING opportunity for kvfree") + +@script: python depends on org@ +p << kvfree.p; +@@ + +coccilib.org.print_todo(p[0], "WARNING opportunity for kvfree") -- cgit v1.3.1