6.6-stable review patch. If anyone has any objections, please let me know.
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From: Joe Hattori joe@pf.is.s.u-tokyo.ac.jp
[ Upstream commit b9784e5cde1f9fb83661a70e580e381ae1264d12 ]
As of_find_node_by_name() release the reference of the argument device node, tegra_emc_find_node_by_ram_code() releases some device nodes while still in use, resulting in possible UAFs. According to the bindings and the in-tree DTS files, the "emc-tables" node is always device's child node with the property "nvidia,use-ram-code", and the "lpddr2" node is a child of the "emc-tables" node. Thus utilize the for_each_child_of_node() macro and of_get_child_by_name() instead of of_find_node_by_name() to simplify the code.
This bug was found by an experimental verification tool that I am developing.
Fixes: 96e5da7c8424 ("memory: tegra: Introduce Tegra20 EMC driver") Signed-off-by: Joe Hattori joe@pf.is.s.u-tokyo.ac.jp Link: https://lore.kernel.org/r/20241217091434.1993597-1-joe@pf.is.s.u-tokyo.ac.jp Link: https://lore.kernel.org/r/20241218024415.2494267-3-joe@pf.is.s.u-tokyo.ac.jp [krzysztof: applied v1, adjust the commit msg to incorporate v2 parts] Signed-off-by: Krzysztof Kozlowski krzysztof.kozlowski@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/memory/tegra/tegra20-emc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c index fd595c851a278..eb2813b51d770 100644 --- a/drivers/memory/tegra/tegra20-emc.c +++ b/drivers/memory/tegra/tegra20-emc.c @@ -477,14 +477,15 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
ram_code = tegra_read_ram_code();
- for (np = of_find_node_by_name(dev->of_node, "emc-tables"); np; - np = of_find_node_by_name(np, "emc-tables")) { + for_each_child_of_node(dev->of_node, np) { + if (!of_node_name_eq(np, "emc-tables")) + continue; err = of_property_read_u32(np, "nvidia,ram-code", &value); if (err || value != ram_code) { struct device_node *lpddr2_np; bool cfg_mismatches = false;
- lpddr2_np = of_find_node_by_name(np, "lpddr2"); + lpddr2_np = of_get_child_by_name(np, "lpddr2"); if (lpddr2_np) { const struct lpddr2_info *info;
@@ -521,7 +522,6 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc) }
if (cfg_mismatches) { - of_node_put(np); continue; } }